Hi Markus I gave up watching SXV as I could not make any sense out the levels at the best of times. I think the complication is the the Adriatic and the mountains. Bob Brown NM7M recounts some strange results at dawn on a 50kHz signal signal skirting the rockies in a QST article.  What happens if you factor in interference between a one-hop and  a two-hop signal ?  My calculation suggest things move a lot quicker. It is difficult to do it properly as the higher angle 2-hop signal penetrates the ionosphere further. It has been very quiet recently and there is very little absorbtion at night for these higher modes. I think this is why the longer paths often show slower smoother changes, because the higher modes are attenuated out of the picture.
 
Cheers de Alan G3NYK