argument against...

no where does it say to add 5 minutes. it defines what gmt hack to write in. for instance, if you land and one minute later you shut down engines, you're not supposed to indiscriminitely add 5 minutes.

some would argue that it defines when to break the forms (781s) if you plan on taking off again (outside of 5 minutes) and/or conduct ground operations before engine shut down.

in the first case, if you land at 0001 then takeoff at 0015, your 781 entry should be 0001 land time with a subsequent 0015 takeoff time annotated as a new entry in your 781.

in the second case (for ground ops i.e. combat offload, backing, etc in the c-17), if you land at 0001, perform ground ops, then shutdown engines at 0015, you still log a 0001 land time.

that's not to say i follow the above argument, it's just what some people interpret.