Quotes online are only as accurate as the information the user inputs.
I can do as many quotes online as I want and I'm usually within $50 from the true premium.
Based on what I've see, the user inputs information to obtain the lowest premium possible and then calls the insurance company saying he wants to go ahead with that quote.
Brokers have to review everything before even entertain the idea of issuing the policy, we pull reports we confirm all info.
By the time it's all done, there are tickets, wrong license dates, wrong coverage, addresses don't match existing address, etc, etc
At the end, the quote is now much higher.