I currently have a NEMA 14-50 in the garage and I am buying a HPWC. I have two choices: - 40 amp charging: Keep the NEMA 14-50 and add connect the HPWC to it through a pigtail. - 48 amp charging: Replace the 50 amp circuit breaker with a 60 amp one, then hardwire the HPWC and get rid of the NEMA 14-50. Which one would you choose and why? Also, what's the difference in range per hour between 40 amp and 48 amp?