sillypoint

I am flying from suvarnabhumi to Taipei on Thai airways next week, economy. Normally I travel light. I can't remember the last time I have checked in more than one bag for the hold. However this time, It would be convenient to check-in 2 bags (total weight around 15-20kgs). On the flight info. it has 25kg limit for my ticket. It says bag (singular). I am wondering if Thai airways strictly enforce 1 checked bag (free) for economy, or just take into consideration weight. I would prefer to use 2 smallish bags to manage the weight while carrying them around. I'll still be taking a small carry-on bag to the plane with notebook, etc. This flight comes under zone 1 on their website, and extra baggage can be bought in advance for just $12 / kilo. Are charges a lot higher at the time of check-in? I realise there are ways around this by redistributing things in the bags once at the airport. Just wondering how lenient Thai tend to be re. multiple bags. Thanks, in advance.