Yah, you're right, I'm wrong again
The slope screw is on the back. I only calibrated it once and got mixed up remembering the note in the package suggested only setting the front screw with the one calibration fluid supplied. That's for the SMS122 ph controller.
During the peak of ph level my Milwaukee ph contoller and Pin Point monitor display the same yet as ph falls during the night the Pin Point displays slightly lower values.