The distance to empty goes up and down very quickly.

It is calculated by the clocks based on the current usage of the car. If you drove 1km down the road very gently the D to G would go up. If you then left it idling for an hour it would still be counting that usage and adjust the D to G accordingly.

If you have an instantaneous litres per 100, I think you will, when you first drive off that will be in the 30s and sometimes higher.

In my opinion they could lose you 200 Ks to go, just driving in and out of the workshop half a dozen times.

If you get in and drive 20ks at a sensible pace, you'll get them all back.

Gavin