The idea is that with the way the physics works it is easier to rotate in the horizontal 1.5 times while going inverted once than doing the same thing but only going 1 time around in the horizontal. It's just hard to do off a kicker with the way the rotations roll out. I have a friend that does cork 3's. They're ridiculous.
PS it's also the same for a lot of riders that doing a cork 7 is easier than doing a flat 7. Going inverted actually speeds up your horizontal rotation.
That thing I do to escape the world and have fun with my friend