Need Help formula ForAll

[PowerApps11]

Hello Community, 

I have a gallery with all outstanding and wanted to take payment, via payment box outside named amount received, I need when I add a value for example: there is two records in the gallery the first record open balance is $100 and second record $50

now if I add amount received box a $100 I would to apply that amount to the oldest record and then amount left to the latest record as the value entered was not enough to clear both records 
Is there a way to do that?

I have tested this but it patches minus second record and not by order

ForAll(
    galPayment.AllItems As aPayment,
    Patch(
        ProjectPayment,
        LookUp(
            ProjectList,
            ID = aPayment.ID  And 'Invoice Number' = aPayment.'Invoice Number'
        ),
        {Balance: aPayment.Balance - txt_OrderSalespayment.Text}
    )
)

When used above formula will patch like wrong as you can see screenshot below it also minus the other record  -$50

[WarrenBelz]

@PowerApps11 ,

If you have not already, take some time to understand how that all works - it will help you with this structure for the future. 

Also another suggestion that may help you get assistance in the future - please read your posts and try to ensure that they describe the problem fully and accurately and any code (posted in Text) is correct. This lets the responder immediately focus on the issue and should help with a quick and accurate reply. I wrote a blog a few years back that may be worth reading.

[PowerApps11]

Hi @WarrenBelz 

The formula is working fine, but currently when I have two records on gallery and I wanted to add a payment to particular one of those records in the gallery to deduct is there a way to do that? 

I have check box inside the gallery already.

[WarrenBelz]

Hi @PowerApps11 ,

I would be approaching that with a separate button for the purpose.