Oh yes, I have very sinister, malignant objectives here.
Some things don't need to be tested. You don't jump off an office block in order to test whether or not the human body can survive hitting a concrete pavement from that height.
Everyone knows NPCs cause a lag, them being turned off when the server reaches maximum capacity. A larger spawn radius means more NPCs will be around one player, or several close together players. This causes higher server load, and thus, more lag.
When do I experience this? All day up until 2 AM when the server was quiet where I suffered between 5-10% loss. I have a crap connection asides from that, but normally it's only between 1 and 4% loss. Since the change it's been between 5 and 10 as said, sometimes going higher.