I play Super Times Pay, and Double Super Times Pay.
I was looking at the Double Super Times Pay on the wizardofodds site. It says just add 0.5% to the base return to get an accurate return.
It than gives a more accurate calculation of the formula: 1.004126984 × b + 0.000921844
I get the "+ 0.000921844" is for the 20x on a dealt royal flush.
But I don't understand the 1.004126984. What I mean by I don't understand, is that I get a different number for the calculation.

I get 1.00190476 for my calculation.
Can someone explain to me how he got 1.004126984, or double check that number with your own calculation?