hmm weird,

if anything it should be the other way round. my ultrapeers have a good balance between I and O and drop between 10 and 30%, depending on vendor, (more recent limewires seem to filter out more). my leaves have some dropped O as limewire (running as ultrapeer) doesn't forward everything to its leaves.

are you sure you're not running as a leaf?
sometimes limewire automatically reverts to leaf if it doesn't connect to enough hosts after a while.