I used a lot of systems. AFAIK, they all give some way for you to set your own transaction ID, and they all provide you with a gateway transaction ID, too. A good system will have a backend process to reconcile records based on one of these and would of course flag anything where the dollars don't match. This is the (inadequately explained) basis of my contention that the price editing is not a big deal. Of course, it could be a big deal if they botched a lot of other things, but by itself it doesn't mean there's an actual serious problem.