Network rendering questions

[Bosseye]

Just some quick questions on network rendering please - I used the helpful guide on network rendering to link my master PC to a colleagues slave PC and it all appears to be working fine, and his slave is apparently managing 85k samples/sec (up from the 14k it was claiming initially)

1) Is it normal for the slave to process less than the master? Mine is running about 200k samples/s. Should his be doing about the same? For reference we have the exact same PC.
2) What affects how much processing the slave machine covers? Machine power? Distance from the master? (his PC is about 200 miles away from mine) Network speed?
3) How does Indigo amalgamate the two sets of data? I don't quite understand the process!

Thanks,