I picked up a set of SC Dirt Web golds and blacks. The inserts seem to be from 2 different manufactures. The gold inserts fill the tire but the blacks leave an air gap between the foam and tire. They are also different colors of blue. Last year, I picked up a set of black barcodes and their inserts were the same way. Is the black SC compounds designed to have a smaller insert since typically they will be ran on lower bite surfaces or is this a supplier/manufacturing issue??