A few questions:
Are you still a 5?
If you're a 4 then why do you want to be a 3?
Are you periodizing your training?
Doing the odd crit won't kill you. Round SoCal you're as likely to win a "regular" season race as you are an "upgrade" race because there are a whole bunch of people figuring they are going to get their upgrade points in the upgrade races.
As I recall you aren't setting the world on fire so I'd temper expectations of success but you learn something every race (well, I do anyway) so keeping the race brain engaged isn't a bad thing.
They really should be called "Continuing the revenue stream" races.
In any case I can't race them because of my license.