500' calls can be programmed to be used only when flying non-ILS approaches.
The 2500' can be suppressed but should sound when rad alt becomes first active, this sometimes can be prior to the 2500' on approach. In turns, if 2500' is reached/lost, this can confuse the logic, as the duration may not be long enough to trigger the aural, similar how it is inhibited when an aircraft passes exactly below for a short duration of time.