So if the physical fit is good, that is, you’re not getting feedback and they don’t physically hurt, and you’re a self programmer, why do you keep going back? Why not just ebay up a PartnerMic for $125 (they’re there, I looked when I first saw this thread) and be done with it? If you’re driving long distances to get to the VA, that gas money adds up pretty quick (that is, the $125 shouldn’t be an excuse). That won’t get you a Roger, but it’s something?
Also, regarding the sounds that bother you, have you gone into the Fine Tuning and Automatic Fine Tuning options in Target and used the options in there? For example, in Automatic Fine Tuning (Open Session/New Session, Fine Tuning tab, Automatic Fine Tuning at the bottom right), you can select from the pulldown menu, Speech - Reverberant Speech or Noise - Party Noise, both of which may be representative of Walmart, and select from the associated pull down if it’s too echo-y, too boomy, etc. You click the Fix Issue button, and it makes adjustments to resolve the issue (theoretically). Obviously you won’t be able to tell if it works instantly but if you have a laptop you could conceivably sit in your car and do this, go in the store and check it out, go back and make further adjustments.
Clearly part of the problem is that you’re just not used to the sound after so long (I’m guessing probably decades?) unaided while you needed it, so that’s playing havoc with your brain. There’s little that can be done about that except more time. Drink some bourbon and go with it, ya know?