We recently had our NEMA 14-50 outlet installed in our garage in preparation for the MS. We used our regular electrician (who is very good) and sent them to the website to download the installation guide. They came, figured out how to run some of the wire inside the wall/ceiling so we'd have less conduit and did a beautiful job. Then I noticed the breaker they put in was 40A. We called them and said, "isn't that supposed to be 50 amps?"
Even though they saw the installation guide early on, it turns out that when they were making material preparations they saw the icon on the charging page (under calculators) that says NEMA 14-50, 240v | 40A. I know why it says 40A there (because the car draws 40), but that can be very misleading if everything is not double checked.
And it wasn't just the breaker they had to change... they had run 8 AWG wire instead of 6 AWG (since 40A only needs 8). So they had to come back, pull out the wire, run a new one and install bigger conduit.
Don't let this happen to you!