Most engines have a tolerance of 1000 per day. If one engine doesn't return result, Fatty will ignore it, depending on the time out parameter that was set in the admin.
I actually have a blackhat desktop program I created a while back that scrapes the results from your PC and then uploads them to Fatty, so your home IP can be used.
Problem is, it's 4 years old and I haven't used it in ages so I don't know if it still works or not...If there's enough folks interested, speak up, and I'll look into it some more.
Side note: If you find Fatty "hanging", check to see if you have ODP selected...It can be notoriously slow, and even unreachable.