IR should be permitted half ticket for children of aged 5 to 12 without giving seat or berth.
IF two children of aged 5to 12.IR permitted to book full fare for the elder child with seat /berth.And another child half fares without seat / berth.
Some small savings for the passenger and if desired separate berth for both children for very comfort travel , then the passenger have to pay full fares for both.
...
more... Omni buses /Air lines also adopted this simple policy.