Out of Round Kumho?

About 2 months ago I got new Kumho Venture Mts. I bought them from Tire Rack and had them mounted and balanced at 4 wheel parts (dont ask). After about a week I noticed at about 20-30 mph the whole jeep would go up and down, not bad but definety noticable. So I put my xj on jackstands so the tires were about 1" off the ground. I spun the tires to see if any were majorly out of round. None of them were perfectly round but there was one that was about 3/8s out of round.

After a month I took them off and I've been running on the stockers for now.

Is that Tire my problem? If so is there anything I can do about it or should I quit whining and live it?

I decided against Kumhos for my Corvette because a lot of people had complained about that very problem on Tire Rack's web site. Of course 40 series tires ride a little differently than Mud tires.