Protein description and "ideal percentages"are wrong

After using my Scale X, it indicates my protein level is on the very low side (13.2%) as calculated by Muscle Mass % - Body water % or 60.1%-46.9%. This indicates that the more hydrated I am, the lower my protein % will be - even though it wants me to aim for between 15.9% and 17.9%. The description of the protein number says “Protein is an important component of muscle development. Protein percentage indicates the percentage of protein to body weight. A lack of protein can lead to decreased immunity, muscle weakness, and anemia”. Nowhere in the calculation is body weight.
Am I wrong or misunderstanding this?