Life is always a lesson. Those that think they know it all usually end up with egg on their face! An opinion is fine but if you quote ‘facts’ make sure they’re right! Cheers!
The regs don’t actually say or define a 13 hour day or 15. In any 24 hour rolling period you must have 11 hours off or 9 hours in any rolling 24 hour period between weekly rests. For same reason you can’t do 16 hours duty and have even 27 hours off as taking a snap shot of the rolling 24 hour period from when you started a 16 hour duty you’d only have had 8 hours off within those 24 hours