Cooking on Yom Tov for Shabbos (II)

We previously touched on the machlokes Rabbah and Rav Chisdah (Pesachim 46b) as to why it is permissible to cook on Y”T in preparation for Shabbos. Rabbah holds that ‘tzorchei Shabbos na’asin b’Yom Tov’, that there is inherently no issur (as some rishonim explain, because the two days share an identical kedusha) of preparation, while Rav Chisda holds there would theoretically be an issur, but we say that ‘ho’il v’iy mikalei lei orchim’, were guests to come on Y”T this cooking would be for their Y”T benefit, hence the cooking act is not defined purely as preparatory for Shabbos. The Aruch haShulchan (495:18) writes that there seems to be some dispute in the Rishonim as to the scope of Rav Chisda’s chiddush. Is Rav Chisda a chiddush in din or a chiddush in metziyus? Does ho’il teach that there is no such theoretical issur as cooking for Shabbos, or in reality there is an issur, but in the context of of guests possibly arriving, what you are doing is defined as cooking for Y”T and not for Shabbos? The Rambam seems to take the former position. Rashi, however, writes that the case the gemara is addressing is cooking after you finished lunch, where the context gives away the fact that you are preparing for the next day. Rav Chisda is a chiddush in metziyus - since the context has changed because there is the possibility of guests, this is not b’metziyus defined as cooking for the next day. The nafka minah is the MG”A previously discussed. According to the Rambam, cooking at for Shabbos is always permitted on Y”T because by definition there is no issur of preparing for Shabbos. According to Rashi (who the MG”A is machmir for), it is only the potential for guests’ arrival which removes the issur; cooking late in the day when Y”T guests are no longer going to arrive would be prohibited.