I have booked two STC award tickets to Finland, 2 segments ZRH-HEL-ZRH, plus 2 domestic segments in Finland. In addition to the usual airport taxes and the annoying fuel surcharge, there's a charge of CHF 76 per ticket with code YF.

YF turns out to be the Finnish VAT of 8% on the domestic segments. However the 76 Swiss Francs equal 8% of the domestic full fare. I find it quite strange that the tax for an award ticket is calculated on the full fare and I wonder if this calculation is correct. Any opinions/experiences?