I'm still keeping an eye open for a dressy white jacket. Spied something by RT but am confused about sizing. The chart shows 4 would be half an inch big if anything, but looking up eBay and seeing measurements much smaller have me questioning if it runs a lot smaller than their charts would lead you to believe. I mean, two of the eBay jackets list 13.5" shoulder and 33" bust. The chart lists 34.5" bust and 27 waist. Do I need to size up in this brand?