Hm, why do you multiplay the upvote value by 0.75 if @tipu message clearly states that 50% of curation coming from the upvote goes to the post author? Curation % depends on the moment of upvote and is not always 25%.
3.608 x (0.75 + 0.25/2) = 3.157
3.157 / 0.76 = 4.153
4.153 - 3.77 = 0.383
This looks like a positive ROI to me.