16 tooth disappointment

I installed a 16 tooth front sprocket today, and I'm a little disappointed.

At highway speeds (75 MPH) my speedometer read +4MPH as verified by GPS and RPM at 75MPH was 6000RPM.

After installing the 16T, speedometer reads the same as before, and RPM at 75MPH only dropped about 300.

I was hoping for 400-500 rpm drop, and some correction in the speedometer, but not what I was hoping for.

Well, so much for hope!