I not getting a lot of responses to this inquiry.
It maybe that a many rec players stand like a statue on the ROS and can do this as most rec players serve is slow.
I am thinking for the 5.0 server and up... which is much faster serve , the ROS player must be nimble on the feet and able to adjust and anticipate with upper body.
im watching ATP players when they return they seem to be like a goalie.
Watching the server and then leaning one direction or another at the early possible sec.