How does Epic know how much royalty to take from kickstarter tiers?

I have read the FAQ multiple times, but I am very curious on to how epic will be able to take royalties from my kickstarter where my tier items are not individual as in the FAQ’s case. The FAQ addressed how kickstarter will take royalty from a tier where the $20 shirt is in it’s own tier of $20 and the game and t-shirt is $40 in a different tier. That I understand completely but my tier system is different as in my standard tier is my game which is $20 and advanced tiers with one in particular being a t-shirt for $55. How will Epic know how much royalty to take? Shall I send them an invoice within 60 days of the kickstarter end date of the purchases(T-shirts, Hoodies, Posters, Etc.), or will they deduct the base game’s cost of $20 from the T-shirt cost of $55. Also, there is a more complex issue at hand, for instance, my last tier of $500 of a service of which I sculpt the purchasers head for use in the game. How would Epic know how much to take from a service I believe should be priced that high? In addition to services without factual cost I am also include a digital artbook with each copy.

Not having your tiers in front of me, I can’t say definitively, but here’s what it sounds like.

Based on your tiers, access to your game is $20. You have subsequent tiers that offer other things (t-shirt, posters, sculpting, etc.). Those rewards aren’t royalty-bearing. So unless later tiers offer additional in-game benefits, the only royalty-bearing amount is $20.

So 5% of $20 for the first tier of $20, but still only 5% of $20 for the $500 tier.

Oh okay, that’s all I needed to know thank you!