Thank you for your reply. Yes, I was concerned about the latter. Up to now, I was not aware of the risk that annotations with lower and upper limit of airspace in fact may do not represent the relevant airspace limits. The radar and flight details warn me on this thanks god, have to change my habits.

A beautiful feature would be an automatic merger of limits, in the example posted above,
display either the full version "1700-6500  6500-FL135" or "1700-FL135", but not "6500-FL135"

Sorry, I'm not actually clear what your question is. If you're saying our charts are missing a piece of airspace, that's an urgent issue, but I can't see that we are.

If you're just saying that the labelling isn't always helpful at all zoom levels, that's unfortunate but is always the case at infinitely-zoomable vector charts. That's exactly what Virtual Radar, the warnings in Flight Details and the ability to easily inspect pieces of airspace is for.

This route crosses the TMA of Szechin which goes down to 1000ft and is airspace D, thereafter crosses a part which goes down to 1700ft and is airspace C. How can I tell this from the map? I get a hint at the "flight details" tab and at the radar at the bottom, but the lower limit of the areas appears to be displayed incorrectly. 

Edit: it relates to stacked airspaces and the map scale, see images 4 to 6: with the iPhone at 1:350 000, the limit of both parts of the TMA are displayed, at 1:500 000, only the upper TMA is displayed (which is dangerous) and at 1:750 000, only the lower TMA is displayed, which is ok if the route is planned at 2000ft. With the iPad mini, only 1:250 000 displays both parts of the TMA correctly, larger scales display only the upper TMA.