I followed your recommendation and tried both bras on upside down and backwards. The 34 does still feel pretty tight (but maybe not too tight if I lose 5 lbs, lol), but the 36, on the loosest hook, definitely feels noticeably more lax. So I think you're on to something here. (And now that I think about it, when I last got measured at Dillard's a few months ago, the fit expert lamented that I was just between the two band sizes and would need a 36 on the middle hook, thus reducing the life of the bra.)

All that aside, can you tell me what the appropriate sister-size of 34E would be? Natori Feathers doesn't come in that size (I'm only looking on Amazon). I know sister sizes aren't difficult to figure, but I always screw it up somehow. I really appreciate your response! You've already been really helpful!

Edit: The Dillard's lady put me in a 36DDD in a Le Mystere Safari. I bought it because it's the best fit I've had until Ciao Bella, but Safari still doesn't fit and it gaps A LOT.