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Now, if we increase the shift size or the number of shifts while holding the other value constant, the number of shares paid will be greater than the average number of shares to find a block and the amount paid per share will be less. You appear to be advocating for this type of change.
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It's best to explain that statement since the way you've written it implies that you'd be rewarded less, which is false.
You left out the point that each share will, on average, be paid more than once ... so result, on average, with the same reward.
Increasing the N reduces variance, not reward.