I had some issues when installing mine, thinking that you leave the IWE actuator in place. I called RCV and you have to remove the ENTIRE IWE. The entire piece shown here (with the 3 bolt pattern) comes out, and the sleeve takes it's place.
It seemed weird to me at the time also, but once I bolted everything back together it made sense.
this also allows you to keep the entire actuator separate, and reinstall it if you ever need to.
Not sure if this is what your mechanic did or not, but hopefully this helps.
