YEs, it works exactly how old dogs said it would
This week I checked in about 24h before the flight, got nice seq 19 as predicted.
As i remember, back in the days of the good grind, you could reserve your seat. Since I was always choosing F-seat, I got later checked in automatically with low seq. This option was removed at least from OWR, and thus high seqs due checking in practically at the counters/security gates.