TDCI high rpm in 6th gear

[yogi_bear_68]

Has anyone noticed the diff ratio for gear 5 & 6 in the Focus TDCI may not be correct?
My car does a fraction over 2000rpm in 6th gear at 110km/h.
According to the specs on the Ford website, the car should be doing 1850rpm.

I've worked it out using the following:
Gear ratio .71
Drive ratio 2.85
Tyre circumfrence 2.000566m ( based on 17" 205/50)
RPM is speed in km per hour /3.6/wheel circumfrence * gear ratio * drive ratio * 60
RPM = 110 / 3.6 / 2.000566 * 0.71 * 2.85 * 60
RPM = 1854

I'm wondering if that's why my fuel economy is usually around 6l/100km even if I drive like a grandma.
eg. Trip from Melbourne to Mt Gambier sitting on cruise control at 100km/h...fuel economy was 5.9
That's a long way from the 'official' fuel economy of 5.6