[Measurement Check] Currently wearing a 32C, calculator says 30D! Problems and shape information inside!

Hey everyone!

I've decided that I'm finally fed up enough with constantly adjusting my bra straps (and just general bra discomfort) and it's time for a new, properly fitted bra.

My measurements are as follows:

1. Comfortably Snug Underbust: 29 inches
2. Tight Underbust: 27 inches
3. Standing Bust: 32.5 inches
4. Leaning Bust: 33 inches
5. Laying Bust: 31.5 inches

As it says in the title, I'm currently wearing a 32C (specifically the lined demi/demi-buste double from Victoria's Secret). About a year ago, I was wearing a 34B shudder, so the 32 has been an improvement, but I'm still having some issues. The problem that I'm having with this bra is that the band feels too loose. When the bra is on the tightest setting, I am able to pull the back of the band (where the clasp is) ~4 inches away from my back. The straps must be set to the tightest setting or they simply fall down. The cups feel like they fit my breast tissue pretty well, except if I put my arms up, the cups kind of 'scrunch up' or bend away from my tissue so that the tissue is no longer contained in the cup. I'm not sure if that is a problem or if it is normal for a bra to do this. My other bra is from PINK and it is a Wear Everywhere Demi in size 32C. It seems to fit a bit more snugly, but with this bra, the gore does not lay flat against my skin. The cups don't seem to 'hug' my tissue, they just sit on top (if that makes sense). If I lift my arms, the gore lifts off even more and the cups do that lifting/scrunching thing, as with my other bra. I can also pull the clasp away from my back by more than a few inches.

Onto shape! After reading through [this] (https://www.reddit.com/r/ABraThatFits/comments/4hwm5z/measurement_maybe_30d_and_shale_i_dont_know_check/) thread, I am pretty sure that I have a shallow breast shape because mine look a lot more like a margarita glass shape than a wine glass shape. My breasts seem to be wide set because the tissue of each starts about 3 finger widths apart. Using [this] (http://i.imgur.com/VPH5K0E.png) guide, I've determined that I'm an 'even 2/5' shape. As for roots, I used an eyeliner pencil after pushing my tissue to the side to draw in a line (as another user suggested), and I think I have narrow to average roots according to [this] (http://bustyresources.wikia.com/wiki/Breast_root?file=Root-width-examples.png) guide.

I was looking at something like [this bra] (https://www.ae.com/aerie-sunnie-lightly-lined-bra-true-black/aerie/s-prod/9793_7552_073?cm=sCA-cCAD&catId=cat7730121) but I've read some conflicting information about Aerie band size-- some say that it runs small and some say that it runs true to size.

Based on all of this information, I just wanted confirmation of size, recommendations on brands, and any advice you're willing to offer!

Thanks in advance, you guys are so awesome. I'm looking forward to (finally) being comfortable in a bra.