The big guy was playing word games and relying on the stupidity of the electorate, plus hoping for an assist (or in this case a blind eye) from the MSM.
He was referring to the rate at which inflation was occurring. Which is to say if the rate of increase was @5% last year and that rate had declined to @4% he was chalking that up as an achievement of his admin and claiming he was bringing down inflation, while it was still increasing, just not increasing at the rate it was previously. 