As you acknowlegde it, "gross" represens the rate or price including sales commission and expenses or whatsoever, however, we Japanese use, just transposing or translating "gross" into Japanese kanakana, "グロス" in our daily life, especially as stock or property market term. I think it is the point how "金額" out of "グロス金額" shold be translated. "Gross amount" looks reasonable for this situation.