Here's more data for Dallas, TX to Lansing, MI:
Car | total trip time | diff | travel time | diff | charging time | diff | supercharger stops |
MY LR (2020) | 19:58 | 1:14 | 17:10 | 0:34 | 2:48 | 0:40 | 8 |
M3 SR+ (2020) | 21:28 | 2:44 | 18:15 | 1:39 | 3:13 | 1:05 | 10 |
M3 SR+ (2021) | 21:14 | 2:30 | 18:05 | 1:29 | 3:09 | 1:01 | 10 |
M3 LR Aero AWD (2020) | 19:26 | 0:42 | 17:03 | 0:27 | 2:23 | 0:15 | 8 |
M3 LR (2021) | 19:07 | 0:23 | 16:42 | 0:06 | 2:25 | 0:17 | 6 |
MS LR+ (2020) | 19:18 | 0:34 | 16:42 | 0:06 | 2:36 | 0:28 | 6 |
MS LR (2021) - alpha | 18:44 | 0:00 | 16:36 | 0:00 | 2:08 | 0:00 | 5 |
MS Plaid (2021) - alpha | 18:59 | 0:15 | 16:51 | 0:15 | 2:08 | 0:00 | 6 |
The SR+ variants have an extra hour charge time and are pushed onto a slightly longer route, using another 1.5h. If there were more superchargers, the additional 1.5h driving wouldn't be necessary - though some driving would still be necessary. Let's say each of the 5 extra stops takes 5 minutes in routing. The shorter distance should shave off another ~10 minutes at least from the necessary charging. That would give a trip time of 20:04.