Drift Boat Regs Question...CA

I have a ten foot "mini-drifter" that I have used for over fifteen years
while fly fishing lakes and rivers in California. Four years ago, I decided
to put an electric motor on it for lake use and because of that, I obtained
CF numbers from DMV for that year. I used the mini-drifter for the next
three years without any electric motor i.e. oars only (drifting rivers) and
because California law does not require registration in such circumstances,
I didn't re-register for those years. I recently went in to update the CF
numbers and get a current license. I was penalized because I had not filed
a "certificate of non operation" and paid triple the usual registration fee.
This does not make sense to me as it was not being used with a motor and did
not require registration for those years. It was not "non-operational". I
fail to understand why once you get CF numbers on a drift boat, you're
obligated to forever register the boat...or face penalties...even if only
being used as a drift boat. It sound like an "either/or" kind of situation.

Do any CA drift boat owners have the reasoning behind this? I suppose I
need to register every year even if I'm not using a motor. It's not THAT
much money but I could not get an answer at a very busy DMV office nor have
I had a response to an emailed question to DMV.

Thanks
Barry