I would be curious to know how the math accounts for draws though.
Draws are half a win and half a loss, just like they would be if you were computing winning percentage.
One difference between the RPI for soccer as opposed to basketball is that in soccer there actually are small bonuses given above and beyond the "standard formula" for beating or drawing against top teams and small penalties given for losing or drawing against bad teams. Anyone who has access to all the results could figure out basketball RPIs really easily, for soccer it's not that simple, and the NCAA doesn't actually tell people what the adjustments are. You can kind of reverse engineer them, but they can also change them whenever they want without telling anyone what the change was.