If I have an extra-productive day, where I accomplish more in 8 hours than I normally do, I don't expect to get paid more. I'm paid a salary, not per line of code.
The Thread Parent has cut down the hours that they are working, and cut their pay accordingly. But they also happen to be consistently more productive in those hours than they used to be. It wasn't a condition of their cut hours that they are required to work more productively, they just happen to be.
(Yes, ideally a good organization would reward this with a higher monthly pay. But that's a separate issue. I get paid the same as another developer in my position, even if one of us tends to be slightly more productive.)
The Thread Parent has cut down the hours that they are working, and cut their pay accordingly. But they also happen to be consistently more productive in those hours than they used to be. It wasn't a condition of their cut hours that they are required to work more productively, they just happen to be.
(Yes, ideally a good organization would reward this with a higher monthly pay. But that's a separate issue. I get paid the same as another developer in my position, even if one of us tends to be slightly more productive.)