It doesn't seem like Bitsler has sports rules listed anywhere (or I can't find them anyway) so I think this would fully be the fault of support.

edit:
linkedit:
It's definitely possible to bet faster than 300 bets per minute too. I haven't sniped a Bitsler wager contest for a few months now, but back when I did, at some points I was doing ~$40 bets (iirc $50 is when you show up on high roller) at 1200 bets per minute.
By the way, it is no longer called wagering contest but XP contest.

My bad, I didn't notice the link at the very bottom of the sidebar. It doesn't seem like there's explicit mention of Asian Handicap rules so imo if support told Bitcoinsummoner one thing that wasn't described elsewhere, it's probably the fault of support.