Now very long time ago I have even studied statistics as a 2nd course-and have worked quite a long time in using it for prognosing where/how to build, but without more clues this wonders me.

But I suspect this is some ´result´ that the mobille pass (whcih I myself have never used till now) proudly tells you what you seem to have covered using your pass. That is not what I call stats-its just counting.

I have been-but not on my current pass-in all countries in EUR-including all 27 of EU, 33 in the pass and also those without own railways. But that took a few more years

The statistics say that you have entered journeys to visit 53 places in 12 countries using 138 trains covering 18000 kilometers. So far, according to the statistics, you have visited 51 places in 8 countries using 82 trains covering 10000 kilometers.

When all journey entered have been finished the statistics should look like this:

If you planned some trips, but you didn’t add them to your pass by pressing the the ticket switch, the statistics will stay incomplete.

Also, manually added trains don’t show up.

If you’re a neat statistic lover, you can just delete the the not used planned itineraries or add them to your pass, and you’ll have a nice overview of the route you did for your memory box :)

Ok but how can I modify a journey that was wrong because of unexisting trains on the offline planner ?

Very often I had to made another journey because when a journey is start using the switch button to add it to my pass ticket, it's impossible to modify. And very often, my journeys had to change because the offline planer gives me a unexisting train or a wrong itinerary or just because of a delayed train.

thanks for any advices.

jeremy 

You can always modify the trains you had added to your pass. You can deactivate the in My Trip and add another one. You can remove from My Trip any trains you didn't use.

If you mean something else, then please give an example.

If the planner doesn't know a train, then you add it manually.

Ok thanks for your answer I managed to delete the part of my unused trains.

I understand that I can add trains manually if the planner doesn't know it. But my problem is more often that the planner gives me trains that does not exists. But that's another problem.

thanks again for your answer, my map and statistics are better now

The first thing to check is whether you have the latest app update.

Additionally, the best is not to use the rail planner app to plan because it is not reliable enough. In its current state, it should only be used to register journeys, not to plan them. bahn.com e.g. is much more reliable.

Just a final remark on 'Statistics':
Every screenshot I have seen says 'up to 90% less CO2 than flying' which made me think that this is just a fixed text rather than a calculated number.

I have been doing planning for nearly fully electric trains, as well as journeys that were fully diesel-trains... but the 90%-number did not change. 
Surely it would be very demanding to incorporate all this in the app, but as it is now, it is just a generic advertism.