Confusing FMS Altitude Calculations

[freeze1058]

Generally, an approach is assigned by approach control, so very rarely would you select an approach on the ground. However, that is still not correct logic for the FMS.

Correct for operations. I was just asking because I recall a different FMS requiring a runway selection (without approach) before flight in order to make proper calculations.

I just did a flight with selecting approach upon descend only and it worked - nevertheless you are right that the current behavior upon selecting approach before flight is not OK.