Tosefta sur Ketoubot 6:9

She agreed to bring in for him [in the dowry] 2 selaim (=4 dinarim), they become 6 dinarim [that he has to pay her back in the event of death or divorce, he has to compensate her +1/2 since he has had use of the dowry in the meantime; see Mishnah Ketubot 6:3]. Whatever the groom agrees [to bring in as his dowry in the ketubah], he puts it in at a value of -1/5, except for the 200 zuz for a virgin or 100 zuz for a non-virgin. (This is probably about evaluating the value of objects he brings in; see Mishnah Ketubot 6:3.) She agreed to bring in for him gold, the gold is like vessels [i.e. are evaluated, so have the -1/5 modification in the ketubah]; golden dinarim, the gold is like money [i.e. are not evaluated, so have the +1/2 modification in the ketubah]. Said Rabban Shimon ben Gamliel: And this is true for any place where the custom is not to exchange golden dinarim [for smaller currency], [but in a place where this is not true] they leave them the way they are and the gold is like vessels.