Hey Ethan,
Before more knowledgeable people come and give you better advice, here are my thoughts 
First of all, if two ramp tests are putting you at 315w, then train with your FTP set at 315w. When on a razor’s edge that comes from doing HV AND Build, adding a few extra percent of difficulty by leaving your FTP at 322w can be enough to push you over that edge.
Secondly, when I am failing workouts every week that tells me I need to take a step back; either I need to give myself some more rest in the form of an active rest week, or I am trying to do too much on the higher end of the pyramid (build/specialties) when my base isn’t where it should be yet.
Were the SSB Base sessions you did last year also high volume? It’s a lot of work, and if your diet/rest/stress aren’t supporting you right now, consider thinking about measures you can take there as well (often that means getting more calories).
You’re already very strong, and it’s good that you’re trying to sort this out now instead of just pushing through to catastrophe. Good luck!