You are correct redirect in is less cpu intensive as compared to redirect out
WCCP redirection can be configured to occur as packets enter a router or switch interface (inbound, or ingress, redirection) or as they are beginning to leave a router or switch interface (outbound, or egress, redirection).
* Inbound redirection - the WCCP process inspects traffic to find packets that should be optimized before the packets enter the router or switch forwarding/routing selection process. Inbound redirection is less CPU intensive than outbound redirection (when using process or other SW based switching).
* Outbound redirection - the WCCP process inspects traffic to find packets that should be optimized as the packets are ready to leave a router or switch interface, after the packet has gone through the router or switch forwarding/routing selecting process. Outbound redirection is more CPU intensive than inbound redirection.
Thanks
-Smita