the other thing the CAA want to see (even more important than just the peak flow) is that the asthma is controlled i.e. are your peak flow and lung capacity readings the same post-exercise as pre-exercise.
If you have to see the CAA for confirmation the the procedure is like this:
2 lung capacity checks and 2 peak flow readings (both times readings must be almost identical or you're asked to re-do them)
6 minute run
2 lung capacity checks and 2 peak flow readings immediately after run
2 lung capacity checks and 2 peak flow readings 10 minutes after run
CAA specialist to review results - they're looking for almost identical readings pre & post as they want to know about any potential degradation of health in stressful conditions.
They also like you to be taking the medication your GP has prescribed, except oral steroids.....they're no-no.
Worth monitoring yourself for that as well.
Good luck with it....I'd say if the military are happy with you the CAA will be.