If someone is turning in wiper time, i can understand why they wouldn’t be approved for AB, just like if an OS applied for qmed.
I have held both deck and engine licenses and ratings for 10+ years and the uscg has yet to tell me i need to pick one or the other.
Now maybe he meant to say you can only use your seatime for one i.e. someone going for dde 1000/4000/unlimited can use up to a quarter of deck time or 180 days (whichever is less) towards a dde. If they were to do that, they can’t reuse that time towards another.