Can you document that?
My understanding was that count was dreamed up by Yankees who feared a loss of power should the South count all slaves as the South wanted to. Yankees didn't want slaves counted at all.The three fifth solution was the compromise.
No, the North didn't want the slaves counted under the circumstances. Slaves were property, the southern owner no more considered his slave his equal as he considered is cow his equal. Slaves had no legal standing in southern society, did not vote, had to rights whatsoever. It was sheer hypocrisy on the part of the Southern delegation to insist that slaves count the same as a free person for the purpose of congressional representation. The 3/5th figure was a compromise.
Neo-Confeds love playing with statistics.
Even if we assume for the sake of argument that there were more abolitionist societies South of the Mason Dixon line (which would, of course, include such places as Maryland, Delaware and DC) the relevant question is what percentage of the Southern population actually belonged to such organizations versus the same percentage in the North.