Distribute all selected object's start times equally between the first and last object's start times. Requires 3 or more objects selected.
distribute
Considering this won't be used more than once a minute and potentially how much time is saved, I suggest the full word distribute, but if a short name is absolutely necessary then distr could also work.
Rationale: I have to manually calculate that often, surely other people do that too, or just eyeball it