PO accrual source of Cost Management is frozen so accruals can't be reversed

We're implementing Receipt Accruals (expense only) and found that the journal entry created couldn't be reversed because we'd get an error "You cannot reverse frozen subledger journal sources".  We were able to update the Cost Management source to not be frozen and then we could proceed with the reversal.  It just seems strange that the default would be frozen if you need to manually update them to reverse.  Being frozen makes sense from the standpoint that its coming for a subledger and shouldn't be changed but they have to be reversed.  Is there an option that we're missing for them