I bought a new car and I couldn't figure out if my license plate has the digit '0' or the letter 'O', so I added both versions to my FasTrak to check which license plate would get charged. It took 4 days after crossing the toll to finally see the charge on my account.

I was about to say "there is no letter O, only number 0" but Wikipedia [0] mentions that California does have both. You can deduce which character it is based on position:

> California currently only uses I, O, and Q in between two other letters, for example "1AQA000".[citation needed]

[0] https://en.wikipedia.org/wiki/United_States_license_plate_de...

Not always. Particularly if you're driving outside of your provider's service area, it may take as long as a week for a charge to show up. I have a long commute right now and I sometimes don't see charges for days.

They (the Fastrack rep) literally told me to wait for days. In my experience there's at least a 24 hour latency.