55%, not 35%. Blizzard’s tooltip is wrong. If you look at the numbers (18 versus 28) and do the math (28/18) you get about 1.555555, which is a 55% production rate increase.
The 35% is the “reduction in build time”, which is a different stat. I don’t know why everyone seems to miss that.
I don’t think the change is a problem, I’m just annoyed that people aren’t getting the numbers right.