Try risking to win $125 at -110. Risk should be $137.50. But the software turns that into $138 to win $125.
OK, decimal points are really tricky, so they round up.
Try risking $125 at +110. Payout should be $137.50. But the software turns that into $125 to win $137.
Oh, now they round down?
Now of course this is just pocket change, but when you can't even bet more than a nickel on an NFL side, this is probably a good chunk of their revenue.