This is typical, and is expected by enterprise customers. Additionally, it's expected that 1 billable day could end up meaning anything from 5 minutes telling a staff tech which wire is crossed, or 15 hours working an exceptionally challenging problem. ymmv, and it all evens out in the end. If you feel like you're getting the shaft over the course of several projects, that's when you know it's ok to raise your rate (or that you need to improve your skills).
Strong relationships are something that has value to me, so if I reasonably can, I'll tend to just do stuff that takes an hour or so for free. Every consulting proposal I write takes 2-4 hours from my life, minimally. The last one I wrote required a 3 person research project over several days. We'd never charge for a proposal, so I'm not going to freak out over 1-2 hours.
(Dave, Jeremy, and Cory might disagree with this assessment.)
If you're ever wondering why I have zero sympathy for designers complaining about "spec work", there you go.