^^I feel like Juice=Juice would have gotten Budokan already if they didn't do the 220 mission.... I'm not sure where they currently are at, I just hope it's soon. (Edit: They'll be at 169 when the growing up tour ends. So I guess no Budokan for them until 2017.)
But yeah, there is a bigger difference with H!P and shadow H!P. UUG had to work hard on their own without a major label or name recognition. I heard that they have to fill 10,000 seats, which is more than what S/mileage needed to fill. Hopefully they earned more loyal fans with People Party Alien so that they can continue having more shows at Budokan.