You have a fleet. Destroyer is in first slot, followed by Starliners. You build another bunch of starliners. So now you have a starliners in first slot. Not good. So you want the Destroyer to be moved back to first slot. How to do it in the least actions was the reason for the question.
If you use order 135 and you use the same fleet number for both boxes, will you 1.) get an error message or 2.) the ship type you indicate will be moved to the front of the fleet?
If possible you rearrange fleet order in one action. If NOT possible (ERROR WILL ROBINSON) then you must move everything to new fleet using two actions (at least in this example as there are only two ship types).
Going to experiment this turn.