You do realize you're not getting 53dB reduction? You take the higher of the two (30dB) and then add 5. You're getting 35dB NRR.
I didn’t realize it was that limited an extra protection, but I can say it works great, for several reasons.
1) If I have to take off my ear muffs, I’m still protected.
2) When both are on, I hear people talking, along with other sounds, even better, because the total noise reduction for shots is great, while I’m hearing everything else, because I have the volume up on the internal ear muff speakers enough to get the sounds I do want through my ear plugs.
It’s a win-win. I can’t say I’m hearing whispers the best, but for everything else, I, and my wife, are fully covered.