Let's be honest, the main reason Sena will NEVER lose Summer HIF in individual routes is less to do with powerscaling and more to have her save face since she's going to lose almost every single time in Winter HIF. HC is the only exception due to her not even competing solo.

Also, Yamamoto is THE SenaP so now that Komino is out of the way he can spread his Sena agenda and include her in pretty much every Step 3 route.