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The math works out a little bit differently

You’re right.

Currently, 0.75x0.75 (authors) and 0.75x0.25 (curators) of inflation.
Post-HF21, 0.65x0.50 and 0.65x0.50

So author rewards would be going from the current 56.25% of inflation to 32.5% of inflation, and curation rewards would change from the current 18.75% of inflation to 32.5% of inflation.

That is closer :) It technically gets even more complicated because 100% of the curation does not go to curators (if votes are placed within the first 15 minutes). But it is the correct line of thought.

Change from 56.25% to 32.5% is only 42.22% reduction.

#sbi-skip