each spring pack not each leaf. you think they have a dude with an anvil and some calipers standing by for when an order comes in?
So you think adding one more leaf is going to solve the problem of a spring pack built for a different weight vehicle?
Leaf springs have differing thickness, length and curve. Obviously to make a proper progressive rate spring pack, you need a stack of leafs that continue to increase resistance as the entire pack is loaded. Adding one extra leaf to make up for 2 or 3 inches of sag isn't going to work unless you add one really thick heavy leaf - which means the pack is going to have s***ty performance. That's why add a leafs suck. If that's what the OP wanted, why would he pay for a custom leaf set? Why not just add a thick leaf to the stock pack?
And yes - they in fact do have a dude win an anvil - unless they just took some random pictures to put on their website...
someone needs to learn to give the correct information before going on multiple websites and attacking a company.