Have seen hot fuelling on numerous occasions, I understand that the TBO of the PT6 is based on cycles as well as hours, and at 14 mins wheels off to wheels on they will run out of cycles before hours if its shut down after each sortie, hence the hot refuelling (have also seen it done as pax are loading). Carrying more fuel is not an option if you want to put 17 or 18 jumpers in it.
Years ago when I did a bit of jumping there, a crowd of fun jumpers started piling into a 208, one of whom was the owner. Someone did a head count and there were 22 jumpers on board, the owner said "She'll be right, lets go!" I was lucky enough to be out of the crush in the only passenger seat, next to the pilot, and the low fuel warning light was flashing as we taxied out..........