Construction WIP schedule

Ryan Duguid is not a registered tax agent or BAS agent. Project support is limited to software issues reproduced with fabricated data. Do not send taxpayer information or request advice, return preparation, tax-treatment confirmation, or lodgement.

+----------------------------------------------------------------------+
|                      Construction WIP schedule                       |
+----------------------------------------------------------------------+
|        AASB 15 construction WIP schedule, from a contract CSV        |
+----------------------------------+-----------------------------------+
| DR  what it gives you            | CR  what it needs                 |
+----------------------------------+-----------------------------------+
| cost-to-cost earned revenue      | one row per unit of account       |
| contract asset vs liability      | cost to date, ETC, certified      |
| profit fade and stale ETC flags  | billings, variations, retentions  |
+----------------------------------+-----------------------------------+

Project name The WIP Tally. Distribution the-wip-tally, import package wiptally, command wip-tally.

Deterministic work-in-progress schedule for Australian construction, civil, mining-services and power-station packages. Review aid. Not a determination.

Package lifecycle: published. Install the-wip-tally from PyPI.

The wip-over-under-billing skill in Australian Accounting Skills (formerly hardhat-ledger) already encodes the WIP workflow. This engine does the arithmetic that workflow consumes: cost-to-cost progress after AASB 15 para B19 exclusions, constrained variable consideration, per-contract contract assets and contract liabilities, and month-on-month profit fade.

The australian-accounting repository contains the maintained source. The the-wip-tally distribution, wip-tally command and wiptally import package are the install identifiers.

In-repo version: 0.1.2; see release notes.

Built by Ryan Duguid, a provisional member of Chartered Accountants ANZ. Written independently, in his own time and on his own equipment.

Not advice

Nothing this engine produces is accounting, tax or legal advice, a journal, a lodgement, or a conclusion that a contract transfers over time, that a claim is enforceable, or that a contract is onerous. Those stay with a person. Confirm the operative AASB 15 compilation at standards.aasb.gov.au before relying on a paragraph number.

Full boundary statement: DISCLAIMER.md.

Install

Python 3.10 or later. No runtime dependencies.

pip install the-wip-tally

Download the fabricated sample contract CSV as sample_contracts.csv to follow the example below.

Use

wip-tally schedule sample_contracts.csv --as-at 2026-08-31

TheWIPTally: 5 contract(s), as at 2026-08-31

  Contract assets:      221,000.00
  Contract liabilities: 183,333.33
  Revenue to date:      3,087,666.67

  Assets and liabilities are per contract. They are not netted.

  Review flags on 4 contract(s):
    ...

The sample is designed to raise review flags. Exit code 2 means a person needs to look; it is not a crash. Exit code 0 means no review flags, and still requires practitioner sign-off. Exit code 1 is a data or file error.

Full detail goes to wip-schedule.csv. Then:

wip-tally review-pack wip-schedule.csv --source sample_contracts.csv --as-at 2026-08-31 -o practitioner-review.md

The pack binds itself to the source and schedule bytes with SHA-256, lists every flagged contract, and puts a sign-off checklist on the page. Keep the CSV beside the pack. The CSV is the row-level evidence.

The reporting date is written on every schedule row, so it is inside the bytes the pack rebuilds and hashes. Give both commands the same --as-at, or the pack refuses to bind one period's numbers to another period's header.

Options

Input columns

Required: contract_id, original_contract_sum, costs_incurred, estimated_cost_to_complete, certified_billings, and outcome_reasonably_measurable on every row. Everything else is optional but sharpens the answer. Amounts are exclusive of GST.

Every data row must carry one field per header column. Leave an optional field empty rather than short. A row with the wrong field count is refused with its row number, because its trailing columns would otherwise shift by one position and read as absent.

A blank outcome_reasonably_measurable is refused by row number rather than read as yes. Both readings state a revenue figure, and the answer to AASB 15 para 44 is a judgement about the contract, not a default this engine can pick.

Dates are not required. This is a position schedule, not a cash-flow forecast.

A --mapping-file JSON object maps canonical names to your headings. Download the mapping example from the maintained source.

The rules it applies

Paragraph numbers below are from the compilation current when this engine was written. Confirm the operative compilation at standards.aasb.gov.au before citing them. The source notes are in docs/aasb-15-source-notes-2026-08-25.md.

Transaction price. Original sum plus approved variations plus the constrained slice of unapproved estimates. The excluded slice is flagged, not booked. Uncertified claims are never added to billings.

Cost-to-cost progress. (costs incurred - B19 exclusions) / (EAC - B19 exclusions). Wasted cost stays in estimated cost at completion, so it hits margin, but it does not accelerate per cent complete. Uninstalled materials are recognised at cost (zero margin) and the remainder of the transaction price follows the stripped ratio.

Contract asset versus liability. Revenue to date less certified billings, per contract. Positive is a contract asset. Negative is a contract liability. The engine never offsets one contract against another. Retention classification under paras 105-108 is flagged for the engagement lead; it is not auto-posted to receivables.

Profit fade. Current margin at completion versus prior-period margin, in percentage points. A movement of 1.00 point or more is a review flag. An ETC that has not moved after $1,000 or more of additional cost is flagged stale.

Onerous contracts. If EAC exceeds transaction price the row is flagged for AASB 137. This engine does not measure the provision and does not post it. Where assets_used_carrying is supplied it also flags para 69 (impair those assets before raising a provision).

GST. Certified billings and retention are shown grossed-up at gst_rate as a BAS review note. Australian progress claims commonly invoice GST on the full certified amount, including retention that has not been paid in cash. This is not a BAS engine.

Tax. Do not carry this progress measure into a tax computation. Confirm the ATO position on long-term construction contracts at ato.gov.au for the year.

What it does not do

• Decide over-time versus point in time (AASB 15 paras 35-38)
• Combine contracts (para 17)
• Decide whether a variation or claim is legally enforceable
• Measure an onerous-contract provision under AASB 137
• Prepare a Security of Payment payment claim
• Lodge a BAS, compute fuel tax credits, or run TPAR
• Replace the wip-over-under-billing skill, which still owns the workflow around this file

Use the wip-over-under-billing skill in Australian Accounting Skills for the review steps. Use this engine for the numbers those steps consume.

Local file boundary

This is a single-user command-line tool. Its input, mapping and output arguments designate files the invoking operating-system account has chosen to read or write; they are not a sandbox. Do not expose the command as a web endpoint. Outputs must have an explicit .csv or .md filename and are written atomically.

Tests

pip install -e ".[dev]"
pytest

The suite pins the worked examples in examples/sample_contracts.csv: a clean underbilling, B19 wastage with profit fade, a constrained mining-services claim, uninstalled materials on an underwater power-station civil package, and para 45 recoverable-cost-only revenue. Test data is synthetic. Never commit client job-cost data to this repository.

Disclaimer

This is an educational tool, not tax, legal or financial advice, and using it creates no professional relationship. Outputs can be wrong, incomplete, stale or unsuitable for a given set of facts. Check anything material against the current standards and the entity's facts, and leave sign-off with a registered practitioner.

MIT licensed.