Yep, I try to suggest using the brand name hub assy's every time.
Sure the offshore stuff is cheaper, but you'll never get much representation or consideration from your suppliers manufacturer ... and in a case where you've had 4 failures, it would be nice to have someone to ask for help. Not necessarily "free parts" ... but at least the benefit of their expertise and advice.
I checked that application and the correct SKF (NAPA) part # is BR930346.
I have attached a screen-print of the available dimensions from SKF's online catalog
Your first 3 were Duralast #DL515024 , and the last one was Timken #SP550307 ... correct?
Timken is a well-repected mfr, so if that is the correct PN, I'd ask Autozone to call the tech line on your behalf, and ask them if they've had any issues ..or ideas?