Lack of Flexibility in 200

We've recently changed from 50 to 200 and I cannot understand how an 'upgraded' system lacks the flexibility of 50? Not being able to edit an invoice, once printed(as mentioned by an earlier comment) is very frustrating. We continually need to issue 'manual' invoices that haven't come through the Sale Order process, as we sometimes have to invoice for a percentage up front or we need to make up shipping invoices with all the shipping details listed - very long winded on 200 as you need to keep adding comment lines. I then need to be able to print these invoices to check the details, but once you print you cannot go back and change any details, surely this should only happen when it's been posted to the ledger, as in Sage 50, and not before?