Let $L$ be a line bundle on $X$. Let $K^{\prime}/K$ be a finite purely inseparable extension and let $q\colon X^{\prime}\coloneqq X\otimes_{K}{K^{\prime}}\to X$ be the natural projection. Then the map $q^{*}$ induces a bijection between the set of model metrics on $L$ and the set of model metrics on $q^{*}(L)$. Moreover this bijection identifies semipositive metrics on $L$ and on $q^{*}(L)$.