Paxboy, Im not too sure how to answer your question exactly whithout actually talking to a Bassa rep but I can certainly hazard a guess...which hopefully wont be a million miles off the fact!
The CC have different working time limitations then the flight crew. CPT already pushes the boundry of the maximum amount of time we can fly as it is one of the longest non-stop flights we operate. Now we certainly can do tech stops but obviously on a long flight the time we have to complete that tech stop is much shorter. Perhaps it was a case that with the time required to make the tech stop and fuel up the plane, it would have put the CC out of hours to operate the remainder of the flight home, either an additional stop would have to be made over north africa our southern europe for the cc to get some rest or they would have to be taken off the plane at the tech stop and allowed minimum hours rest!!!
This is just MY GUESS in the matter so dont shoot me down, I am just lending my opinion. The whole union agreements thing is a confusing one which I find very difficult to understand but just bere in mind that situations such as this are there to maximise the safety of everyone on board! Laugh if you will but until you have actually done the job, dont jest!