Ok here we go. What I found out is that damage numbers vary a lot and I´m not sure why. Maybe there is another luck based variable in the damage calculation. Every single test was done the same, parry and then powerattack while the troll is staggered.

I make three posts, because of the many pictures.
I start with blackmetal sword:

Black metal sword fully upgraded. sword lvl 61.
https://steamcommunity.com/sharedfiles/filedetails/?id=2941344912
https://steamcommunity.com/sharedfiles/filedetails/?id=2941344871
https://steamcommunity.com/sharedfiles/filedetails/?id=2941344954