What you're failing to consider is that this 1.67% of revenue is more like 10-15% of their volume, and that in small package scale is everything. That extra volume lets the carrier load more full trucks direct to smaller destinations, which decreases handling costs (unload, sort, reload). This is why small package carriers give such large discounts to big accounts. The top line decrease would be small, yes, but losing the volume would INCREASE operational costs.