I've noticed that some of the TMA frequencies in Switzerland does not match with the correct ATC-unit. For example, around Zurich, SD mentions "Zurich Information", but this is only the FIS-frequency and they can't give clearances by themselves. For TMA crossings "Zurich Terminal" is the correct ATC-unit to contact in TMA-airspace around Zurich for VFR-traffic in class C. For crossings within the non-TMA and non-CTR airspaces (class C and D), "Zurich Delta" is the correct ATC-unit. They give for example clearances to cross corridors and in general class C airspace above FL100/FL130.

In Germany, the non-CTR airspaces in class D and C doesn't have published frequencies for VFR-charts at all, but they are mentioned within the IFR-arrival/departure charts as Radar frequency. For example around Suttgart, this would be "Langen Radar" on 125,050 or 119,200 and around Cologne/Bonn, this would be also "Langen Radar", but now on 135,350. The problem here is the German ATC-company "DFS", which want to force VFR-pilots to contact FIS first prior to cross airspace class C or D.

Sorry, the split between airspace definitions and area control definitions is so jarring that it's a complete non-starter for us. We'd be trying to use that data for something it isn't strictly supposed to be being used for, by creating a weird mapping that isn't entirely clear, and expecting our data maintainers to keep on top of it, error-free, when the country itself wants us to use the FIS frequencies for any VFR pilots wishing to gain access to those pieces of airspace.

Our best bet is to campaign for the authorities to change that recommendation, if you wish SkyDemon to advise different frequencies than the FIS frequencies.