Overdrive Light - Not Too Bright (not that I should throw stones)

[maxrider]

Confused about the RPM I get vs the initial chart listed on page 1 with OEM specs.

I have lower RPM with the indicated speeds, I initially thought this to be due to the change in tire size(195/55/16) but comparing the tire calculator, there is not sufficient data to support that :
180/60-16 195/55-16 Difference
Diameter inches (mm) 24.5 (622.4) 24.44 (620.9) -0.06 (-1.5) -0.2%
Width inches (mm) 7.09 (180) 7.68 (195) 0.59 (15) 8.3%
Circum. inches (mm) 76.98 (1955.33) 76.8 (1950.61) -0.19 (-4.71) -0.2%
Sidewall Height inches (mm) 4.25 (108) 4.22 (107.25) -0.03 (-0.75) -0.7%
Revolutions per mile (km) 823.06 (511.42) 825.04 (512.66) 1.99 (1.24) 0.2%

Somebody set me straight .

Did I already have a lower RPM running engine before?

Or is the cart off in the numbers:
OEM Gear Drive
MPH - RPM's

70 - 3100 (so here i dropped 100 rpm)
80 - 3600 (here i dropped 450 rpm) this is a very noticeable drop.
90 - 4000

New Gear Drive
MPH - RPM's

60 - 2200 (Saw it on a later ride)
70 - 2600 (500 less RPM)
80 - 3000 (600 less RPM)
90 - 3400 (600 less RPM)