hello99 –
Yes, he’s mechalek between mino and eino mino by ????”?, I am well aware of that. But he only does so since a ????”? is already assur and only has a tzad heter, so in order to make it like the same kind he adds the factor of eino mino. But this distinction is only in ????”?, which only has a tzad heter. Regular heter b’heter, according to his understanding of the Gemara in Menachos, is never batel even if is aino mino, and this is pashut pshat in that Gemara which requires only ????? and not also ??? ?????. With all due respect you are misreading the Ran.