No encryption takes place on the client. Unless you have your instance and client tools installed on the same Windows host.
All encryption is server side. The client statistics can be skewed by what is happening with your client in terms of rendering the data, other processes, etc. Don't use those.
The server statistics can be skewed as well, unless you limit what is running on the instance and host.
It looks like your test shows encryption has some overhead in terms of the set statistics IO stuff. I'd run that a few times, average out the values.
There isn't an easy way for me to give you a script that tests things. Run a bunch of queries, and average things out.