Get info based on a flaged field

[Fred in Thailand]

I have been working on this for over a week. It seems so simple but I can't figure it out.

I have a table called construction payments. It contains records of payments needed to be paid during the construction phase of a condo building project by clients who have bought condos in the project. There are three phases to the payment process.

Phase 1) The contract signing phase where the client pays a deposit and a down payment.

Phase 2) The construction phase where the client pays based on a payment schedule.

Phase 3) The balance is over a fixed time frame. (Mortgage)

What I have done is put the first two phases together in the construction payment table. The third phase is handled alone in another table.

I now need to track payments for the two phases separately but keep them in the same table for accounting purposes and reporting.

I have added a field (constructionflag) that I want to use to track the construction phase payments.

I calculate the total to be payed during the construction phase and record the payments made. The problem is that the payments are not always made according to the payment schedule. Sometimes a client will pay a lump sum that may cover a number of future payments (in part or completely). What i need is a calc that will total only the flagged payments so I can use that to arrive at a balance due for the construction phase.

Remember the table also tracks the first phase. I had no trouble tracking the overall totals but this has me stumped.

I have tried everything I can think of but nothing works. It seems that it should be easy.

Total of construction phase payments due - total of constructions phase payments made = balance due.

[Fitch]

Make a calc field [ amt*flag] and then calculate the total of that.