Question about hearing protection

I have a question about the consistency of hearing protection.I have used 3 different ear pros in the limited time I have been shooting.MPOW from amazon nrr30 is okay didn't have to double up either to comfortably shoot.3m Range Rental nrr30 was pretty good didn't have to double up to comfortably shoot.Worst one 3m 1436 nrr 23 couldn't shoot pistols without ears hurting, required some foam earplugs and even then it wasn't very good.I tried a set of Walker Razor Slims, and I thought they were really good however I didn't shoot with it yet. Since the nrr is the same as the garbage 3m 1436. Should I be worried about shooting indoors using the Walker.Thanks via /r/CCW https://ift.tt/2PoWPmE