Comment by retsibsi

They'll never be cent-accurate, but if you've done a decent job then they should be in your zone of rough indifference. Then you can simply avoid that annoyance by not looking at the final price, safe in the knowledge that at worst you may have missed out on a marginally worthwhile purchase by marginally underestimating its value. If that's not the case, you didn't bid enough in the first place.

(But also, how is the annoyance not irrational? Your estimates weren't cent-accurate, but they were just as likely to be slightly too high as slightly too low. And you haven't learned anything new about the true values -- unless you take your emotional reaction to be new evidence. For your emotional reaction to be new evidence, it has to be somewhat unpredictable, otherwise you could have fully factored it in in advance. But you seem to be saying that you're predictably going to be annoyed by a 1c loss.)