PaulS:
It is pointless to print a value from each sensor, then operate on different values. Read each sensor ONCE on each pass through loop(), and store the value. Base your if statements on the values you stored, NOT on new readings.
I'm not sure if I understood what you were trying to say. The if statements are based on one stored value. The robot adjusts depending on a difference from the stored value.. If you were telling me to store a value for the background, it wouldn't work due to the track I am working with (inconsistent readings).