Firstly, no 1 will know which session you are doing except the admin who in-pro u and yourself. When u go for RT, u just join in the training according to your colour tags. There is no such thing as all the 19th session people in 1 group therefore there is no increase in training intensity as u progress.
Secondly, what do u mean by another 20 sessions when new starts if u can't clear RT? Every year if NSmen opt to do RT, it's still the max of 20 sessions. There is no increment in the number of sessions.
I remember when I did RT at Maju earlier this year, they divided people within my colour tag into different groups eg. 1-5 sessions, 6-10 sessions etc. When you do the mass exercises, the "older" groups are supposed to do more reps per exercise. For running, the "older" groups have to run more rounds. Depending on your number of sessions, there is a single-digit number to be slotted into a small plastic slot on your number tag, this identifies your group ie. Blue tag Group 2. Of course it all still depends on the PTIs, some of them ignore the groupings and make everyone do the same amount.
As for the "another 20 sessions", I have edited my earlier post as it was based on my recollection of the enhanced program guidelines when it first came out a few years ago. At that time I distinctly remember reading of this extra 20 sessions in new window if still failed RT in previous window, it was such a drastic change that can't forget. I just went into NS Portal to check and seems they have removed this extra 20 session requirement, maybe due to negative feedback. Sorry for posting based on outdated info.