>>101942031
There's 3 tiers to PUP's. Regular, L, and SP. SP is the pricier one and it's usually because it's a lot more difficult to manufacture and yeah Mouse's drill hair with the streaks and the like falls into that category.

Funnily enough I know of only other SP PUP, and it's that because of the plaid pattern requiring such meticulous work lol. Also as I was typing this Goodsmile just tweeted it again >>101941774 so here's the official announcement https://twitter.com/GoodSmile_US/status/1941294153842803140