Invoice validated date

Hello Friends

I have a requirement to get the date that the invoice is ready or cleared for payment which means that the invoice is validated, approved and ready for the system to pick the invoice for payment

Do you know which columns I need to consider to derive the date

IN detail here is the issue and requirement

I have just discovered that the report I have been using to create the Process Compliance stats is flawed.  I currently run the custom written report by the AP transaction header GL date on the assumption that this date is updated whenever accounting is performed for the transaction.  Thereby the last date on a transaction that has been accounted and approved for payment is the date that the invoice is ready for payment. I have now found that this is not the case so I am failing to report the lifecycle of an unknown number of invoices. I need to be able