Amortise the anticipo before the last estimacion

Put four things on the contract record: the amount of the anticipo, the parts it is granted in and the purpose of each, the fianza de anticipo that secures it, and the proportion at which it will be amortised, which follows from the anticipo against the contract amount rather than from a negotiation.

Яагаад: Everything downstream reads these four numbers, and each of them lives in a different document today: the amount in the contract, the security with the insurer, the proportion in somebody's spreadsheet. Recorded once against the contract, the monthly amortizacion is computed rather than remembered, and the person who computes it in month nineteen does not have to have been there in month one.

The anticipo is invoiced on its own CFDI when it is received, not netted quietly against the first estimacion. Record the UUID it was stamped with, because the CFDIs raised against later estimaciones have to relate back to it as the anticipo is consumed.

Яагаад: Without that relationship the same peso is invoiced twice: once when the advance arrived and again inside the estimacion that repaid it. Both documents are stamped, both are real, and the excess is only found when somebody totals the year's CFDIs against the contract amount and gets a number larger than the contract.

Place the orders the anticipo was granted for and mark them as such: the site installations, offices and stores and the movement of plant against the first part; the materials and the permanently installed equipment against the second. Keep the spend traceable back to the part that funded it.

Яагаад: The anticipo is granted for named purposes under the LOPSRM, and the convocante can ask what it went on. That question is easy in month two and impossible in month twenty. There is a commercial reason as well as an audit one: an anticipo spent on general cash flow leaves the works with the materials still unbought and the repayment already running.

Apply the recorded proportion to what the estimacion earned and deduct that, so a period that measures more repays more. Show the amortizacion as its own line on the estimacion and on the CFDI raised against it, next to the fondo de garantia rather than merged with it.

Яагаад: A flat monthly deduction is the standard error and it fails in both directions. Too small and the works finish with the anticipo still outstanding, which turns the final estimacion into a debt; too large and it takes back the working capital the anticipo was granted to provide, in the months the job most needs it. Proportional repayment is self correcting and needs nobody to watch it.

Put the anticipo granted next to the amortizacion taken to date and carry the difference forward as a running balance, with the period it is projected to reach zero. Compare that period against the programmed completion every month, not once a year.

Яагаад: The balance is the only figure that answers what you have really been paid, and it is the one nobody prints, because the estimacion shows the month and the ledger shows the cash. It also governs two other things: the fianza de anticipo stays alive while any of it is outstanding, and the unamortised part sits outside ajuste de costos, so a claim computed over the whole certified value quietly overstates itself.

Two or three periods out from completion, check that the remaining work is enough to absorb the remaining balance at the contract proportion. Where it is not, deal with it while there are still estimaciones to deal with it in, and take the settled balance into the finiquito rather than discovering it there.

Яагаад: An anticipo still outstanding when the works finish stops being an advance and becomes a debt, payable in cash rather than out of work, and it holds the fianza de anticipo open and its premium running. Found three periods early it is an adjustment to the amortisation; found at the finiquito it is a cheque.