My calculation is that you added only some 9 quarts of a combination of anti freeze and water. Don't know what your cooling system holds, but certainly more than this,,,like 16 quarts or more.

If so that leaves some 7 plus quarts not accounted for,,,,likely residual water mixed with vinegar,,,h**l only knows what your pf level should be by now, but certainly not what your calculations suggest it should be. Vinegar being highly acidic and all!

Have you ever opened up your block petcocks?

I would be highly suspicious that your cooling system still contains a certain level of old gunked up coolant also.

All in all the reason that I have always relied on the Prestone reverse flush system.