PG&E has a number of calculators on their site, the one your used may or may not be accurate. I just noticed they have a fairly new EV calculator - this could be wildly inaccurate, because it makes broad assumptions. In fact you don't even have to be logged in to use that one, and you only answer a couple of very basic questions. It does seem to mostly assume you're on the basic E-1 Tiered rate, and probably based on what you say is your currently monthly bill, that most of your EV charging will push you into the higher tiers.
The problem is that the EV rates are TOU-based, so this calculator doesn't know when you use your current household electricity, nor when you charge your EV, to make an accurate calculation.
There is another calculator. If you have 12 months of electricity history with PG&E, and your meter is a SmartMeter, then you can log in to your account, and use the Electric Rate Plan Comparison tool. This will use actual 12 months usage by your actual TOU, to calculate your bill on EV or E-TOU rate plans, compared to your current E-1.
This tool can actually work better if you DON'T have much history of EV charging in the previous 12 months. Because after you use the Comparison Tool, there is an add-on calculator called the Rate Simulator with five basic questions - one of the five is buying a new EV. This Simulator still uses your 12 month history, but the EV question will add on additional EV charging and on top will assume you charge at the most advantageous hour (for the EV rate this would be like midnight to 7 am). The other four questions also check if you would modify other behavior like the dishwasher to shift to off-peak periods.
If your 12 months of history already include EV charging, then don't use the add-on Simulator, but your 12-month history won't tell them when you were charging, and how to predict you expected time-shfiting to the Off-Peak periods.
