If you had a flight, it had to go in the F700, Auth Sheets and Log Book. Therefore, if it flew, it flew a minimum of 5 minutes; you cannot have a flight in any of these documents that lasted zero minutes!
Does any flight HAVE to be recorded with at least 5 minutes flight time?
My understanding has always been that flight times should be rounded to the
nearest 5 minutes, therefore flight time of 0 - 2 mins 29 secs should be rounded down to 0 minutes. As long as auth sheets, F700 and log book tally not sure what the problem is.
My best effort was in very light weight Nimrod. PABTO from Lossie 23 to Land Kinloss 26 (in those days) where we were definitely trying for under 2' 29". Didn't crack it though (but only just) so 5 minutes is in the log book.