Ok. That's good.
Are you sure your male is indeed a male? How old is he and how much does he weigh? Is this the first time either of them have been bred? I'm surprised that you didn't witness a single lock.
Are you sure both of the measurements were accurate? How many prey items did she eat between the two measurments? What type and what size?
Also, Ball Pythons that have been large and just lost weight tend to gain the weight back rather quickly. That's still a lot of weight to gain in just two weeks...