I guess the feature (cancel matched order within x sec) is more gear towards live-market market maker?
For a typical market we can just contact admin and have them void the match order if it were too late.
Thanks for answering all the questions

I think it's also used to quickly ping the odds source that you're using (for example if you're hedging on Pinnacle) and make sure that their odds haven't changed when someone places the bet so that you're not accidentally taking a bet on stale odds.