Although it might cost you more, you might get more for your money if there is a Costco near you and you got one of the newer HA models that Costco carries, unless you need tinnitus management. If you have health insurance, it might ~ wholly cover the cost of HA’s at Costco. I get $1,000 per ear every three years on my insurance, enough to cover the cost of a “defeatured” HA at Costco.
My Quattros needed refurbishment at the end of my three-year warranty because of poor external mic function, and I thought I’d get replacements with new batteries. But as I reported in the forum about a year ago, the replacements that I got, although they had great sound, did not come with “good as new” batteries. I didn’t have to pay anything for my in-warranty replacement. Perhaps, since you’re being charged and have been promised new devices, you’ll get that. If you decide to go the route you described, I’d check to be sure and complain if you don’t get good as new batteries.
A bit off-topic relative to your situation (but maybe not the one I described for my refurbished under warranty HA’s above), I’m getting an EV in the coming months. I read the EV battery warranty: 8 years or 100,000 miles, whichever comes first if the charge capacity drops below 70% of the original full charge under either condition. However, the fine print says the replacement is totally at the discretion of the OEM and could be a new battery, or it could be a refurbished battery similar in age and performance to the battery that failed the warranty test. So, that got me wondering what the fine print is on rechargeable HA battery warranties. The horse is already out of the barn door on my Quattros. Still, in the future, I’ll be checking to see if the OEM only promises to deliver a refurbished HA with a battery that’s only good enough to get me across the finish line of the warranty period and nothing more - which is the kind of warranty I took the EV battery warranty to be.