Edit by way of posting: at most, we could increase the amount of matches by removing the 24h play time limit if the matches are played in two different (perhaps officially recognized?) sub-metas.
For an example:
I play at current time (10:00 GMT I think) with JCJ on standard ruleset. In two hours, we'll play a Speedbuilding meta duel, and in 8 hours we decide to play again on 50% upgrades rules. All 3 matches are valid for standings.
The 10 match limit would also be applied only for matches in a single meta.