I ran the example given (added bigger table to give reads but almost exact) and I could not reproduce the behavior. 

.Net SqlClient Data Provider

RPC:Completed

exec dbo.myProc @myparam = 'ALL'

358 reads

SQL Query Analyzer

SQL:BatchCompleted

exec dbo.myProc @myparam = 'ALL'

358 reads 

kay brought up a good tip also, but it's hard to say what actually is the issue in your environment

-Max