48- דבר אחר

i was asked, why does the gemara describe תכשיט or צדקה as דבר אחר? what's the secrecy?
I think the answer is that the Gemara/ברייתא/מר עוקבא is trying to hint that the דבר אחר is not the same by the 2 cases discussed in the sugya - which are נשטתה and יצא למדנה"י, i will explain.

according to Rashi the question of what is דבר אחר is only in in the case of נשתטה, meaning how much do we give her, only tachsit or do we also take צדקה from him, what rashi is bothered by (explains rav elyashiv) is tosfos question that how can one say she is not entitled to תכשיט? its part of the obligation of כתובה? therefor Rashi learns that its going on the case of נשתטה describing what she gets, either תכשיט only or we even take צדקה from him, but in the case of יצא למדנה"י surely we cannot refrain from giving her תכשיט. comes out that although דבר אחר means ,תכשיט in the case of נשתטה it means צדקה in the case of מדנה"י

according to tosfos, the gemara is discussing the case of יצא למדנה"י however the translation of דבר אחר doesn't stay the same by נשתטה, because according to the translation of תכשיט, meaning that we refrain from giving her תכשיט, still in the case of נשטתה not only do we give her תכשיט but we also take צדקה from him. in other words this is the source of the rambam that although he paskens like תכשיט still in the case of נשתטה he lets בי"ד take צדקה as well. to wild???