The way those spec sheets work is you start with a base truck with no upgrades, with it's price and weight.
As you ad upgrades like the bigger engine... it ads cost and weight to the base or generic truck. That's the figures your seeing, Cost and weight over a stock engine.
edit: The zero's represent a standard part included with the base truck, with no increase in weight or price.
My C-15 was 719 lbs over for an 01 model...pre Acert. My sheet doesn't show the cost, but they have gone way up it looks like.