I sent them a mail yesterday, curious to get a reply.

I do remember now how it went last time I checked in at Thai Smile counters: had 40kgs, Royal orchid silver, was allowed 30 and had to pay around 550B at Thai customer desk, not funny, many people buying tickets, I had short connection time flying in from Europe, then get back to check in desk....

Previous years bought Thai domestic business class tickets and no problems with up to 55kgs, biz tickets too expensive now.