Ah something slipped through! It should be three. I’ll push an update later this week.

That is actually correct. It’s the fiddliest bit of the game. Grade both has a value and a die associated with it. There is a table on page page 25, in the item section, that breaks down how Grades and their associated dice interact. I’ll add a bit more of an explanation earlier too, since it is the most confusing aspect of the game.