ip route cache flow

ip flow ingress

ip flow egress

As of current information, we need to use only one of these command on sub interface of router from where traffic is flowing out to WAN.

2. Can we use combination of these commands on interfaces ? and if yes how ?

3. Any document from Cisco which gives clear idea on IOS versions supporting "ingress" and "egress" commands ?

I had referred below URL for the same, but still doubt is not clear.