2055 or 2089 would be in millimeters; maybe your computer uses centimeters, so you would input 205.5 or 208.9, thus the decimal point.

These values are different by about 1.5%; do you need better accuracy than that? If not, just pick one, or use the average. If you want better accuracy, you can do a rollout test - lay a tape measure on the ground, line up your valve stem with the end of the tape, roll your bike along the tape until the stem is again at the bottom, and read the tape at that point. If your tape is in inches, multiply by 2.54 to get centimeters.