After quite a bit of testing I've come to the conclusion that f2~interact is stance specific (at least against some characters). Here are some alternate combos you can use that achieve basically the same damage that aren't stance specific. I've updated the OP.
(low) b12, 21~interact, b3, bf1, ji2, 111 32% 30% +
(overhead) b2u3,b1~interact, b3, ji3, f21~db2u 40% 38% +
(overhead) b2u3, ji2, 1~interact, b3, ji3, f2~df2(MB), f21~db2u 46% 44% + *
(low) b12, b1~interact, b3, ji3, f21~db2u 38% 36% +
(low) b12, f23~df2(MB), 21~interact, b3, 21~db2u 45% 43% + *