If it were really .8% AFR, then the odds of Clevor getting 4/5 bad drives would be 0.000000004063232 or 124/30,517,578,125. He would be over a dozen times more likely to win the California lottery! No, I don't think so. 10%+ is more likely.
All hard drive manufacturers are bound to have some bad drives. I've never used a WD, but I'm sure they are not much worse than the rest.