That engine/ds ratio is not accurate and it could be important in trying to figure out why it won't get over that MPH hump.

An engine rpm/ds rpm ratio of 1:1 = zero slip. If your ratio was truly 1:1, the engine rpm and ds rpm would be the same. I agree with Dizuster's suggestion that some parameter in that channel needs to be changed. Only other reason the ds rpm could look like that is that the sensor is not reading correctly which is not out of the realm of possibilities.

In the first screen shot you posted, it shows engine rpm at 6,494 and DS rpm is 3085 which calculates to about 2.1 though the field says 1.0. In the above pic, the ratio calculates to about 5.0:1 (7,514/1,486) which can't be right on any planet, even Planet Itis!
.
A ratio of 2.1 actually seems closer to reality and good or bad, would calculate to around 20% slippage. Is this the same unit you had before you changed stuff? Maybe post what the engine rpm and ds rpm are at the shift points to compare. My guess is that if it's more efficient off the line than at the stripe it's too loose?

Racepak engine/ds ratio