Thanks 'Hareesh Mangalam/73888 for your tip. It really helped. I booked ERS to SBC on 16315 with bookin from SRTl which gave quota of 220 seats instead on 94 from ERS.
Now I have a CNF on SL class.
Thanks again!
My other friend tried booking on 22607 and could not get. Anyway great to have in 16315 :-). Saved money :-)