I'm not sure what your first paragraph means "The purpose of GL Account validation (has) ....nothing to do with inactive accounts..."

I had the first choice selected (Account-Department) and it seemed to be first validating the GL account without a tie to the department so in Invoice entry -> New Invoice Detail -> Acct/Dept (without any Distribution selected) I type in a GL account (as explained previously we have GL accounts that are inactive and then the same GL account with a dept (ie. GL 7710 no dept is inactive but GL 7710-100 is active), I get the error "G/L account 7710-is marked inactive".

I had thought that Account-Department would look at the pair but it doesn't even let us enter the department, I type 7710 and tab over to enter the dept and I get the error. So I changed the option to Account only-dept on file just to test it, same result. So I changed it to Account only (again just to test it), same result. So I changed it to None since it was the only option that would work, except it doesn't work and I get the exact same result. It seems that these options are not working as they should, at least Account-Department and None seem to need a fix. It seems Andrew is saying that a fix is in the works to correct the Account-Department option so that it won't validate against inactive accounts so that is good, I'll use that option once the fix is done but None as I understand it should not do any validation so why am I getting the same error?