Saddle height? Inseam minus 10cm?

saddle height should be 76.5 using Dutch's equation. Actual height is 78cms which is most comfy for me.

Thus You didnt measure Your inseam correctly. Apparently You were too lenient on Your balls.. lolz Most framebuilders would tell You to measure Your inseam with a stick that is firmly pulled up against Your crotch, as if Youre trying to lift yourself with the stick. Agreed, its somewhat uncomfortable. But its used because it really shouldnt matter how well You`re hung when choosing saddle height

Then the maths would have made sense and You`d have Your 78 cm.