I should probably add that I'm being a little pedantic. For your broader point, the journalists could more accurately say that "the year-on-year percent change

I should probably add that I'm being a little pedantic. For your broader point, the journalists could more accurately say that "the year-on-year percent change in the CPI eased to x% from y%" to be more accurate, but I think most people who are reading it understanding that saying "inflation eased to x% from y%" to be a shorthand for that.