Accelerating universe? Not so fast

[Underseer]

http://www.sciencedaily.com/releases/2015/04/150411091607.htm

Astronomers have found that the type of supernovae commonly used to measure distances in the universe fall into distinct populations not recognized before. The findings have implications for our understanding of how fast the universe has been expanding since the Big Bang.

I am a "cosmic inflation" skeptic, flame me as you will. This finding supports one of my primary quibbles with that hypothesis: the use of the type 1a supernova in measurements of cosmic distance. That it also has implications against dark energy (or matter) is just icing on the cake.

So the expansion of the universe isn't accelerating as much as we thought, therefore the expansion of the universe is not accelerating?

How does the logic of that argument even work?