The TC = +4 at the pivot point with any number of cards remaining. TC = +7 when your RC is 3x the number of decks remaining.

For example, I use an IRC of -7 for 8D. The PP is +25. Suppose there are 3 decks remaining. Then, 3x3 = 9, or RC = +34 for TC = +7. With 2D remaining, 2x3 = 6, or an RC of +31 for TC = +7.