Good advice that. And if you'd like to learn more about the most "efficient" way to level up, Zwift Insider is an absolute wealth of information, and/or ask here.
(And then you'll know why even those of us at stupidly high levels still insist on finishing to the nearest whole km after every race )
It's just an ingrained habit to get the extra 20XP that you no longer need
I still do that too - can't finish a ride at 19.8km, needs to be a nice 20km