Yes, that's how WCCP works.
How the data gets spread is based on what you choose, mask or hash, and what hash you use.
https://notalwaysthenetwork.com/2015/02/05/deep-dive-into-load-balancing-with-wccp/
The other thing to note is you want to make sure the acl you use on the firewall has denies for the 2 WSA's. Otherwise you can end up with loops.
access-list WCCP_Redirect extended deny ip any object-group our-Internal
!WSA1
access-list WCCP_Redirect extended deny ip host 172.16.15.10 any
!WSA2
access-list WCCP_Redirect extended deny ip host 172.16.15.27 any
access-list WCCP_Redirect extended permit ip object-group our-Internal any
wccp 90 redirect-list WCCP_Redirect password *****
wccp interface inside 90 redirect in