"Not every 'limitation' has to be written down or even verbally specified to be worth adopting. Try it as an airmanship 'limitation' if it applies to your operation."
If there was a real problem with starting the APU during fueling, the manufacturer would have told you (either in the 'limitations', service bulletins)... Trust them ... they built it.
still if you arent too comfortable with it... dont do it... thats just plain personal comfort.. for airmanship its atleast gotta have a reason... and if you have a good enough reason .... specify it... put it in writting so others may benefit from it (your aircraft manufacturer might appreciate it too!)
