Hold the lever down for 3-4 seconds to dump the entire tank during a flush. The flush tube drops too fast.
The 1.27 GPF are about the ragged edge for flushing.
Had a customer with the Hi-Lo twin flush toilet. (Lo #1 and Hi #2)
All is good until a house guest hits the wrong button after taking a dump.
I happen to be an engineer for a major company that makes dishwashers. Yep - you’re correct. DOE regulations limit amount of water and energy during cycle.
Guess what? It’s only getting worse with forthcoming 2019 regulations!
BTW...messing with flood float won help. It’s only there to prevent a flood situation. Water levels are software controlled.