The three source spreadsheet: why the owner's monthly position is rebuilt by hand
Somewhere in every owner's organization there is a spreadsheet that holds the project's position. It has a tab per month, or a column per month, and a set of formulas that someone understands. That someone spends the second week of every month rebuilding it, because the three documents it draws from arrived in three formats and do not agree with each other.
This post is about why that happens, and why it is not a failure of the person maintaining the spreadsheet. The problem is structural. Three sources with different purposes are being reconciled into a fourth document with a fourth purpose, and nothing in the process stores the reconciliation.
Source one: the pay application
The G702 and G703 arrive monthly. They are the contractor's statement of billing against the schedule of values. They are certified, which makes them the most reliable of the three sources for what has been billed. They say nothing about forecast, buyout, pending changes, or cause. They often arrive as a PDF, which means the figures are retyped.
The schedule of values lines on the G703 also rarely match the lines in the owner's budget. The contractor organizes by trade and by subcontract. The owner organizes by the GMP exhibit, by funding source, or by the board's approved budget categories. Every month someone maps one to the other, and the mapping lives in their head.
Source two: the contractor's logs
The contractor keeps a change order log, a contingency log, a buyout log and an allowance log, usually in Procore or a similar project management platform. The owner may have read access. These logs are current and detailed, and they are the contractor's. Classification of a change is the contractor's classification. A contingency draw is recorded when the contractor records it. The owner has no independent record of what was approved when.
The logs also change. A PCO reclassified in August changes the August position retroactively, with no trace. An owner who copied the log in July and copies it again in September finds that the two copies disagree, and cannot tell whether the difference is new activity or an edit.
Source three: the owner's own record
Emails approving a draw. A board resolution approving a change order. A meeting note where the architect accepted that a conflict was a design gap. A memo from the owner's rep disagreeing with a classification. These are the owner's independent knowledge, and they live in inboxes and meeting minutes. They are the source that would matter in a dispute and the one least likely to be in the spreadsheet.
A fictional $33 million middle school illustrates the gap. The contractor's log shows a $210,000 PCO classified as owner scope. The owner's rep has an email chain where the architect acknowledged the item was missing from the drawings. The spreadsheet shows the contractor's classification, because that is what was copied. The email is filed. At closeout, the owner has paid for a design gap out of owner contingency and the record of why sits in a mailbox.
Why the rebuild happens
Each month the three sources are pulled, mapped to the owner's structure, reconciled where they disagree, and typed into the spreadsheet. The reconciliation is the valuable work and it is the work that is thrown away. Next month it is done again from scratch.
What a second ledger changes
The fix is not a better spreadsheet. It is a separate record that belongs to the owner, is organized by the GMP exhibit, stores every entry with a date and a source, and is never recalculated from someone else's data. The pay application is imported as certified figures. The contractor's logs are compared, not copied. The owner's own approvals and classifications are entries in the owner's ledger with the email or resolution attached. When the sources disagree, the disagreement is itself recorded as a flag.
Costwitness is that second ledger. It holds the frozen GMP baseline, the owner's change order register with cause classification and audit trail, the contingency ledger, the buyout tracker and the allowance register, and it takes a stored snapshot each month. Comparing it to the contractor's log takes minutes instead of a week, because the comparison is line by line against a record the owner controls. The software keeps the record. The owner's team still decides what each disagreement means.
What to do this month
- Write down the three sources your spreadsheet draws from and where each one lives. If there are more than three, write those down too.
- Pick one change order and trace it through all three sources. Note where the classification or the amount differs.
- Save this month's spreadsheet as a values only copy with the date before rebuilding next month.
- Start a simple owner's register for approvals: date, item, amount, who approved, and a link to the email or resolution.
Questions on this
Can the owner just use the contractor's Procore logs as the record?
The owner can read them and should. But they are the contractor's record, organized for the contractor's purposes, and they can be edited without the owner knowing. An owner who relies on them has no independent position in a disagreement and no history that matches what the board was told.
Is a shared spreadsheet with the contractor a workable middle ground?
It removes some retyping. It does not resolve whose classification governs, and it still lacks a stored history. Both parties editing the same cells usually means neither party can say what the figure was last month.
What if the owner's rep maintains the spreadsheet?
That is common and often works well while the rep is on the project. The risk is continuity. When the rep's engagement ends or the person changes, the mapping and the reconciliation logic leave with them. A ledger with stored entries and a documented structure survives the handover.
In the product
GMP baseline, Change order register, Monthly owner report. Free tool: Pre-GMP Readiness Score, Change Order Exposure.
Keep reading
Earlier: The cash flow S curve: planned against certified, with a forecast. Later: The one page report for the board and the lender. All articles on owner reporting.
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