Sorry, not true. The signal carrying capacity of the two cables is identical. What is NOT the same is the power loss. That means that any cable carrying power (for most installations, that means the cable between the SWM LNB and the power inserter) should be solid copper core if it is reasonably long (100ft or more). Maybe you have never installed systems with that sort of length between the Power Inserter and the LNB.
If it's a traditional (non SWM system)using a non-powered multiswitch like the WB68, then all the cables carry power, because the LNB is powered from the receivers, so they should all be solid copper unless they are short.
Really---
What I can tell you from years of experience installing
Old Legacy systems will run without any problem on CCS, and can do some crazy long runs 300'+
SWM will run without problems on CCS up to 200'.
The only place I am seeing solid copper needed is on runs over 100' for clients.