Not Buick, but ? about long term fuel curve

[Front Mount]

I have a 2002 Chevrolet Prism - yes I know it is a Corrolla. Anyhow had my scan tool hooked up the other day while driving and saw the long term fuel curve was + 24% while cruising at 3000 rpm. At idle it is +6% which I could see an older car using more fuel due to carbon on valves, vacuum leaks etc, but 24% seems really high. Is it like our Buicks and mean it is 24% higher then original program? I know our cars read 128 as programmed and higher is adding fuel and lower number removing fuel. Car runs great only a 3 speed auto and gets 28-32 mpg. Just curious what it means. Short term fuel curve was going between + and - and small numbers and seemed normal to what I expected.