In re-reading the Three Fifths Compromise it seems to me that the compromise worked against the south by not allowing it to count the entire slave population and thereby gain greater representation for its slavery causes. The Compromise speaks of 3/5ths of an entire population not 3/5ths of a single person - in other words, for purposes of representation, only 3 slaves for every 5 slaves were to be counted. To count more than 3 slaves for every 5 would have given the south an unfair and nearly doubled representation.

I too could be off in my interpretation but it seems clear in the reading. However, like most Compromises, this one could also be open to misinterpretation.