Why are your “finish range” values negative?
It would be interesting to divide actual distance travelled by reduction in reported range to see how often you were under par and over par. Above 1 - travelled further than the estimated reduction in range. Below 1 - travelled less.
Yes, confusing entering finish range as negative, but they are the kms unused at the end of the day, so Tank kms used = Start Range + Day charge + Finish range.
We were not rushing (enjoying the scenery, and generally had to spend at least 4 hours driving from check out time to check in time), so probably achieved an average close to Tank range overall.