Unfortunately (fortunately?) yes, I think you may be off on this one.
I think a lot of what you’re talking about is whether you hit meaty with the cubes or not.
After the f+H wallbounce, you’ve almost completely recovered, and are tossing out the second cube inside of them instantly… basically they’re landing on two cubes together.
The second combo has you recovering later, and bouncing them on top of two consecutive cubes (and has more hits for more hit decay), so they’re more likely to pop out… I think it works in the corner anyway?
Try this missile assist combo from just outside the corner:
f+H and Doom missile, wallbounce, L-Cube, launch, jump straight with immediate L, modok kicks like crazy, missiles hit, air M-balloon bomb, air dash d/f S (spike), OTG c.M into HBR/HPB/assist into whatever.
The sweet part is that I don’t think they can air recover out of the air L (I’ve never seen it at least), so at the end of a longass combo when all your hit decay runs out, I think you can always still finish with this sequence, rack up a ton of hits for damage (80k-ish?) and still get to OTG into super/assist/whatever afterward.
…and it looks ridiculous too. lol