Excellent. Here's hoping they do keep the flights going for the whole year as the global air travel market gets back in stride. The add-ons are passenger service charges, airport fees, security charges, taxes (from both ends) plus, plus. It's a pretty standard but unique set of add-ons depending on the origin and destination. Always been that way.
I am on a very low bandwidth satellite connection so can't get the airfare breakdown, but if you check out
matrix.itasoftware.com/search
and type in your PER-BKK flights and select the TG flight, that should throw up a page that gives a precise breakdown of the airfare being quoted. Matrix isn't a booking website, but it's very good for finding flights and checking airfares.