Dethflare doesn't depend on SS, it depends on time and time only. 3-4 Deathflares is a 3 mins fight. In this fight, you will get 1 extra Ruin3 in the beginning and 1 more Ruin due to regen, maybe 1 more if the fight is on your side and it lasts 4 mins. So, 2-3 Ruins3.
I will get 3-4 Ruins3 and more potent DoTs. Sorry, I can't argue with math.