Consumption by major new units

Hey, guys.
So far you have helped me very well.

Let's get this straight.

I got the car a month ago with an average consumption of 20.5 L in normal driving mode.
If you drove gently then it was about 19L.

So up sleeves and up to the bacon.

Problem Thermostat (other thread) has now improved, after about 10 km it has now temperature.

Lambdasonde, this has had the Symthome as in the FAQ. So new (no Bosch) bought and built in, Symthome away, better response, seems to work.

Finally, OBD there and read out. Error G62 defective. also fixed. Great.

The last error in the memory is the brake light switch, which I will order and replace now, but then the OBD is empty.

Now I had drunk and am on the road, but still reluctant, because wants to recognize the consumption.

Result, tank is now 1/4 full - driven 343 km to 80% gentle overland, some city and once highway (130 km/h - 25km, once briefly accelerated to 220 km/h).
So I get up to about 460 km with a tank filling (tank each time about 70 L - E10) (70 / 460 *100) so about 15,2 L.

I find the result for my act. I know you can't drive the car with 10 L, but my expectation was so 13-14 L about.

What else can it be, what should I trade again? I still have the 3.6L motor with me, so I can use (as far as I know) most attachments and if it is only for testing.

Give me a hint, please. Thank you very much

-- Audi V8 , built in 1993, 4.2 L with chip, climate is always off, seat heating only sometimes on. BBS 18" Allufelgen with 225 tyres at 3 bar, underrun protection is missing. --