Why do two dog food brands recommend different amounts for the same size dog?

Two dry foods can differ by 50 to 100 kcal or more per 100g depending on fat content, ingredient sourcing, and formulation, and this difference alone explains why one brand's chart shows a noticeably larger or smaller gram figure than another for the same dog.

A food with 450 kcal per 100g will always recommend fewer grams than a food with 350 kcal per 100g for the same daily calorie target, and this is entirely expected rather than a sign one brand's chart is wrong.

Brands also make different underlying assumptions about typical activity level when building their charts, so one may assume a more active average dog than another, adding a further layer of difference beyond calorie density alone.

The way weight brackets are grouped also varies between brands, so a dog near the edge of a bracket may see quite different figures between two charts even before calorie density is considered.

Rather than comparing gram figures between brands directly, calculate a calorie target for your dog independently, then convert to grams for whichever specific food you are actually using, based on its own calorie content.

This approach gives a consistent, comparable result regardless of which brand's chart you started from, and avoids the confusion of trying to reconcile two charts that were never meant to be compared directly.