Is this request primarily for an option to manually set the transaction amount applied date? Would this be desired when creating the transaction and applying it to invoices, or at any time afterward?

There is no need to change the current logic or functionality of the date received or date applied, there is also no reason to want to manually edit the date applied. I would like to suggest that you simply add a column named "Date Received" on the Invoice template and this should solve the problem in the easiest way.

In addition to what the OP has said, I would like to add some information. The way I understand it, there are 3 possible scenarios:

1. For automatic merchant or non-merchant payments when the customer makes the payment the date received is the same as the date applied, so there is no problem.

2. For manually entered payments, for example if the customer pays with a check or cash, then the invoice would display the date received which would be the date of the actual transaction when the check or cash was physically received, and the date applied would be the date we sign into Blesta and apply the payment. This way the customer is happy and our accounting records are improved.

3. If the customer prepays or receives a credit to their account then the date received should be the date the transaction is actually made where the funds are actually received, then the date applied should be the date when the credit is eventually applied to an invoice.

I hope I was able to provide some clarification and a simple solution to the problem. There are some threads on the forums that would have related information.

https://www.blesta.com/forums/index.php?/topic/4084-date-received-instead-of-date-applied-for-transactions-on-invoice/

https://www.blesta.com/forums/index.php?/topic/10372-set-date-received-vs-applied-date/

Thank you.