How long do SE blades last? This is third shave with the blade and it seems even better than the 1st shave
With the 1912 I've managed to get 10 shaves out of that SE blade but I only do 2 passes.
The reason it may have felt like a better shave is your first 2 shaves helped smooth out the rough edges of a new blade. I also find this to be the case with Feather Artist Club SE blades.