Good riddence to this waste of time bus "service". Wait in the airport basement for up to an hour and breathe diesel fumes from all the other busses. Then get in a cranky old bus with plastic seats ( ie sweaty) and spend up to 2 hrs in start stop traffic to get where you could have gone by train or taxi in 30 minutes. Yes, it was cheap, and you certainly got what you paid for - ie very little.
And yet when Don Muang was the main hub they used to run a very fast reliable shuttle into the Sukhumvit. Which incidentally had a stop opposite Soi 8 for the Nana skytrain.