[Stocker]

I've never run across that situation and I have always run P-rated tires on our Tacoma (I know, apples / oranges but it's still a light truck). My K20 gets Load Range D tires (8-ply rated). Seems like all you should need is tires with a load capacity equal to or greater than your truck's maximum weight rating. Maybe your tire retailer is ill-informed or extra cautious? Have you tried other retailers? This might be worth a call to Tire Rack or America's Tire for a better answer.