With computer system changes it's just impossible to predict. We "went live" on a new system Jan 5 and some of the problems we are having never popped up during testing. Though you want everything to go smoothly, it's never going to happen with a major systems change. I've had to say far too often - "i'll have to call you back after the system comes back up" and though it drives me crazy it's not unexpected. Or when the system is running fine, I say "I'll get the info and call you back" because it seems to take so long (compared to our old system which we knew) to get any information. Frustrating on both sides of the conversation.