[Larry]

I would suggest that RAF orders specifying the bomb load for each mission would have always been carried out.

However if some aircraft within a Sqn were required to carry different bomb loads from others then there could be last minute changes if one of them when unservicable before take off.

It may have been possible to get a replacement aircraft to fly the mission but not necessarily in enough time to get the same bomb load as the unservicable aircraft.