The bags always seem to make the estimate for high-performance, super-active dogs at that weight--our dogs get a fair amount of exercise each day running around the yard and chasing turkeys, but if we fed them the bag-recommended amount of food, they'd end up way overweight.
So if she's at a good weight, I wouldn't mess with the amount she's getting.
"We are--each of us--dying; it's how we live in the meantime that makes the difference."
"It's not what you gather, but what you scatter that tells what kind of life you have lived!"
"Be kinder than necessary, for everyone you meet is fighting some kind of battle."