Thanks for the replies, guys. Sorry I wasn't more specific in the original post, I was in a rush trying to get it posted and get to my kid's game on time. Anyway..
The method I used to pinpoint the problem machine(s) was to traceroute from my home computer to my servers, and then from my servers to my home machine. I then pinged each IP along the route from both sides until narrowing the problem to two particular IPs within my host's network. This has been a long-standing problem, and is always involving the same two IPs.
Daniel - your suggestion of 1% or less within the host's network is right in line with what I've been reading elsewhere.