tire wear

[vinconco]

I put new michelins on about 7000 miles ago. The old ones had worn perfectly (rears slightly more than the fronts) but even wear across the tires. I replaced the shocks, bilstiens front and ranchos rear and the tires, (michelin LTX MS) same as the old tires. In about 4000 miles I noticed a choppy stair step pattern worn across the front tires. The wear pattern was even across the tire and both front tires were worn the same. The rears were wearing normaly. I took them back for rebalancing and while they were out a little it wasn't enough to cause the pattern of wear of that extent. The tire guys said it might be the shocks... but not the new BILSTIENS... . say it isn't so. Remembering when I installed them, one package didn't have the cone shaped bushing so I just re-install the OEM bushings. Could this be the culprit?