“Representatives and direct Taxs shall be apportioned among the several States...”
Correct. So why are you arguing the issue? It tipped the representation in the house towards the south.
“Representatives”
Homer said that slavery takes away half of a man's worth. So allowing 60% was slightly better than that.
There is an interesting passage in John Adams' writings where he observes a group of maybe 12 slaves doing a piece of work which 2 men could have easily done more quickly. Obviously the slaves were being clever--they had no incentive to finish the job quickly. This was probably in Washington, DC, towards the end of his term as President.