They charge passenger basis & amount is based upto demand, passenger type (not-fixed)
The IRCTC update is:
1. Rs. 10 service charge is for sleeper (Ticket based)
2. Rs. 20 for any type of AC & FC (Ticke Based)
So...
more... kindly check, if any agent is levying Rs. 10/20 per passenger, as irctc charges per ticket, irrespective of passenger base!!!