Part of the problem I pick up here is that, in general, engineers who haven't done the hard work of the actual scoping themselves tend to be wildly optimistic i

Part of the problem I pick up here is that, in general, engineers who haven't done the hard work of the actual scoping themselves tend to be wildly optimistic in their estimates. I'm not sure if this applies to more seasoned engineer-customers though. The more experienced engineer-customers (people who've been working for 10+ years) tend to be far more understanding here.