He's talking about using a NIJ rated soft armor in place of a trauma pad beneath hard armor plates. You or someone else would have to shoot it to see if it provides any significant increase in protection. When you're talking about improving LVL III hard plates you're talking about wanting to stop .30-06 and up, I don't think an extra layer of soft armor is gonna do that for you, therefore I see little benefit in it.
Edit- and YES, you do need something soft beneath those plates. I wouldn't dispense of them just to shave a few ounces or bucks, as I mentioned earlier if you take a 5.56/7.62x39 round to the plate is going to leave a nasty bruise even with trauma pads. Wouldn't want to know the effects without them.
Sgt. of Marines, 5th Award Expert Rifle, 237/250
1st Award Expert Pistol, 382/400
D Co, 4th CEB, Engineers UP!! OEF 21JUN-20SEP2011