TgO Lev27:18 :וִיחַשֵיב לֵיה כהנא יָת כַספָא עַל פוֹם שְנַיָא דְאִשתְאַרָא עַד שַתָא דְיוֹבֵילָא‏ : the priest should calculate the money for him according to the years remaining until the jubilee year
See the entire entry for ˁal pum, ˁal pem prep. according to