This is a long standing question of mine. If I set a start time before an object reaches its greatest altitude using the planner, hit OK, then increment, decrement or edit the starting altitude on the Target Settings, it changes the time to after the target had reached greatest altitude. For example, define a target at 1h +45 deg w/ start altitude 55 deg and the start time is set to 6:46 p.m. (for 11/11/2019). Increment the start altitude by 1 deg (from 55.3 to 56.3) and the start time jumps to 12:56 a.m. Is this expected? I understand there are 2 times w/ a particular altitude so it would require some tricky code to make this work the way I expect.
By the way, an RA of 0h 0m 0.0s is considered invalid (w/ a message in the planner Error box). Actual invalid RAs & Decs cause the planner to not show a graph (ok) but there is no error message in the Errors box.