This is unscientific, but if she looks too skinny feed her more. If she looks just right keep it the same, and if she looks chubby, tomorrow she'll probably look just right :)
Feeding puppies is not really about what the bag says, but how they do on the food. Maverick ate around 350 grams/day plus treats (a lot of treats) until he was almost a year. We bumped him up to around 500 grams (plus a lot of treats) but he started looking really skinny and losing weight. Now, at almost 16 months, he eats about 950 grams/day. I hope all of these calculations are right as I used a converter I found online.
We had a schedule of 3 feedings a day. 6am or so, noonish, and 6pm or so plus treats for training and a snack before bed. While we don't feed a noontime meal anymore, we still give a snack before bed. We used the "too skinny, just right, or too fat" method above and aside from the very beginning, we never really changed it. If your puppy looks good on 25 grams per meal, then that's all she needs.
Edited to say: She looks really young and small. She seems pretty healthy, maybe a little on the small side, but definitely not starving or anything.