I have an ongoing project billed by the hour, everything is perfect.

This month I negotiated new rates for a couple of assigned users to this project. So I edited the project, updated the Rate Per Hour and all the historical money calculation in the project was updated with the new rate which is wrong, so all numbers are wrong.

Cost per hour have an Effective From option that avoids this scenario, I don't see why we don't have it in Rate Per Hour, unless there is another way to handle this that I couldn't find