I added some evaporated milk to the base I made at weekend after watching CBM's video.
It certainly adds something. I can't categorically state what. I wouldn't stress if I didn't add any to my next base, but if there is some at hand, I will probably use it again.
Didn't thicken up though. Quite the opposite. Took a lot longer to thicken, or maybe I am making my bases runnier now with more experience...I don't know.