Summertime Condensation!!!

My wife and I recently bought a 4 year old 2,400 square feet single level modular home. It is an "on-frame" modular with the entire bottom covered with a vapor barrier material. We live in North Carolina where the humidity is pretty high most of the summer. I have all of the foundation vents open and we keep the inside temperature around 72 degrees. I've noticed that on days that have really high humidity levels some condensation forms on the underside of the home on the vapor barrier. It's only around the areas where the ductwork enters the floor. It's not like it's dripping rapidly, but it's there nonetheless. From what I can see the barrier is doing it's job because the insulation is always dry. When the condensation does build up enough to drop there's protective plastic covering most of the ground under the house. I'm sure this is fairly common and doesn't appear to be causing any problems with the foundation. Due to the way the home is built there's no wood exposed and I haven't seen any mold or mildew whatsoever. What drops onto the plastic dries in a few days. I've also noticed that when the humidity drops the condensation disappears completely. Is this anything to be worried about? I've considered using a dehumidifier, but they're fairly expensive and this isn't a problem that happens too often. I happen to have some pellets that are used in a container to absorb the moisture. That's my only option for now. Should I be concerned or just consider it a part of nature? Thanks for any info!