Read what I said again.
Your odometer is accurate within a couple of percent; there is some unavoidable uncertainty due to the range of tire sizes and an allowance for tread wear (which reduces the rolling diameter of the tire). You are not getting cheated out of "mileage money" at work; you are not overpaying your lease payment. The odometer on my Mk5 is well within 1% of the kilometers indicated on highway markers on trips of several hundred kilometers.
The speedometer reads high, and so do ALL vehicle speedometers. They are REQUIRED by regulations, both here and in Europe, to never read lower than the actual speed even with the worst-case tire/wheel combination under worst-case treadwear conditions.
EVERY vehicle speedometer reads high. EVERY SINGLE ONE. They are REQUIRED to. The only difference is the AMOUNT that they read high, and that depends on the range of tire sizes that the manufacturer approves.
On the Mk5, the speedometer reads around 5% higher than actual speed. If you KNOW this, and you know what the local police will put up with, you can take this into account ...
WHY IS IT LIKE THIS?
Think of what would happen if a manufacturer ever produced a vehicle in which the speedometer showed less than the actual speed. (Remember, there is no such thing as perfection, there is always some error. Yes, the rotation speed of the wheel is known with digital precision, but the circumference of that wheel is not.) The lawyers would have a field day in court as a result of all the people blaming their speed (or their accident) on the wrong speedometer.