Two of our teams do billable professional services for customers. Many of the people on those teams forget to enter their billable time occasionally. The best way we've found to catch those mistakes is to have them track non-billable time as well. That way if their total for the week is less than 40 hours (our standard work week), their manager can just ask them to go back and fill in the billable or non-billable time that they forgot.
This system works well, but now we have a concern that tracking all their hours might create a risk that they will be reclassified as non-exempt employees. They are all skilled professionals with a lot of control of their own schedules, so we think the risk isn't too large. But the employees don't want to lose the flexibility to work a bit extra one week because a customer needs them and a bit less the next week because their projects are done. And management doesn't want to worry about paying overtime, since we already work hard to maintain a 40-hour average for everyone to promote work-life balance.
Does anyone have alternate ideas to ensure that employees track their billable time consistently?