Assigning effects to a group not worth it? (counter intuitive)

I want to share somethins I was discussing with Greg Ondo and what I´ve found is counter intuitive for me.
I usually have some vocal tracks which use mostly the same effects so I decided to put these Inserts in a group and route vocal tracks to this group.

But what I found is that Case A is more CPU friendly.
Case B show a higher CPU usage (5% to 10% higher Asio Guard meter), is not that much but enough to have audio dropouts in my case while it should be the opossite way as there are much less plugins involved.
Isn´t the purpose of groups help us in these scenarios?
Using Cubase 13, Wndows 10, Ryzen 9, project with 15-20 tracks with several plugins each.

Welcome to the discussion.

Hmmm, we’ve read several times that a lot of inserts in a single track can lead to thread overload, and asio spike, and sometimes it would be better (even if not logicall) to spread few inserts through more tracks. But in your example there’s exactly the same number of inserts, and a whole lot more of them in case A (and for the record I routinely have done B for years and years) So what could be happening?