Slavic Y-DNA is approx. 15%, according to the study.
Assuming South Slavs entered Albania with 80% Slavic Y-DNA lineages, an arbitrarily chosen percentage since no official data exists (and South Slavic modern distribution includes some recent Albanian lineages turned Serbian/Montenegrin) implies that an additional 3.75% Albanian Y-DNA are reintroduced Balkanic lineages, for a total of 18.75% South Slavic Y-DNA lineages.
18.75 x 0.55-0.7= 10.3125% to 13.125% purely Slavic ancestry from males /2 = 5.15% to 6.56% total Slavic autosomal contribution from South Slavic men.
If Slavic ancestry in Albanians is, say, 25% total autosomal, doesn't that imply most Slavic ancestry came from women?
This is all assuming that Slavs entered as South Slavs, as the study notes.
If the study is perhaps wrong as @Kari mentioned, and they came in as pure Slavs, 15% Y-DNA still is only 7.5% Slavic autosomal (assuming 1:1 boy/girl ratio), so to get 25% total Slavic autosomal means 35% of Albanian women lineages came from a Slavic woman.
This is all implying 1:1 ratio of boys/girls. It's also possible sons to Slavic men were killed off more often, while daughters to Slavic men survived far more, so extrapolating from Y-DNA may not even be accurate unless these dozens of variables are all accounted for...
Basically, most scenarios, whether South Slav or pure Slav invaders, favour a larger Slavic female source in Albanians.
Again, this is my amatuer understanding.
