ugh, see I hate when people say their 25" poodle weighs X amount, and then there's another 25" poodle who ways 20lb more, and yet BOTH can be PERFECTLY FINE! If either of them lost or gained anything they'd be skinny or fat. Height does NOT equate weight, not even in the same breed.
Generally you want to be able to feel the ribs fairly easily, with maybe a touch of covering (and don't forget poodles can have pointy hips too!) A good general idea is if you lay your hand flat and feel across your knuckles on top of your hand; a dogs ribs should feel like that. For some that means 40lb, for others that means 60lb!
me and Jak have noticed that a lot of american dogs seem to be big builds, cos they're all way heavier than our guys! lol
Paris is 25" and is 39lb. She is skinny though! lol.