Just a side note... if you are considering Fromm... which by the way is an excellent food. You may also want to consider American Natural Premium. It's made at the same plant as Fromm from the same ingredient (give or take a few depending on what formula you're looking at) and is at a much more reasonable price. I just say this because before we got our girl Roxie we were spending an outrageous amount on EVO which is a great food but at over $50 per 30# bag it was pretty pricey. Our breeder turned us on to ANP and since Roxie has been on it since she was pretty much on solid food she has had a gorgeous coat. Just a thought since you are in the same area. Hello neighbor by the way... we live not too far from about half way between you and Milwaukee.Charlie, our now 6 month old basset is petite like your Maggie. She currently weighs 21 pounds. At 11 weeks, Charlie actually weighed in less than Maggie.. only about 7.5 pounds. She was also pretty "skinny" at that time. Although, the vet said she was healthy! Even though you could see her ribs, she still looked healthy. She wasn't the best eater at that time either. We switched her food from Eukanuba to Iams and she just never really seemed to be excited to eat when we fed her Iams. (That is just her personal preference, ha! She is back on Eukanuba, but we are actually going to be switching her over to Fromm.. a local Wisconsin brand.) At that time, she sometimes skipped breakfast and when she did eat, she was very pokey about it. Now she is back too being very very excited when it comes to meal time. She also is filling out more or less. She isn't skinny but she doesn't really have much fat on her either if that makes sense. (You can check out pictures in the photo gallery).
I guess my encouragement to you is that I am sure Maggie is fine and I am sure she will catch up with her weight sometime soon. Maybe, though, there would be a food she may like better? Just a suggestion. I am sure she is just a joy and I am really glad to hear that you nursed her back to health.. even if your first vet couldn't do so!
Oh.. and the basset I grew up with was named Maggie. (Maggie May). I love that name for a basset