There's not much to understand. There's nothing logical in how they apply an increase (except for "Hey FSCO we lost money, here's the accounting proof, we need 25% hike across the board ...No problem SF, here we go, enjoy."). Meaning, if you have a spot clean record, your rate would have most likely gone up with SF, at least twice in the last year or so. For SF it's all about where you live (so they can paint us all with the same brush in the the same area), not so much about your personal record. This alone to me should be illegal ... LOL
Anyways your only choice is to leave SF for something less expensive. There usually are choices, at least there was one for me ... we will see for how long and then it will be a time to switch again. Screw the loyalty they were trying to sell me before I left ... until they are willing to revert a loyalty and clean record!
To Viffer. I have seen you claim that rate decreases do happen and I understand that there's always someone somewhere who gets one (without much of sensible logic applied). Well as you might guess, in the last 10 years, I've had none. So therefore I'd believe that rates only can go up ... LOL (would you blame me?)