A lumber pack simply presents you with a defined packaged of wood for a fixed price. They’re a simple, confident way to buy random width, random length lumber within some definition of random sizes.
Conversely when you buy by the board foot (Bd.Ft.) in any quantity you want, there are lot of variables from available board sizes to shipping charges.
There is no difference in the wood, it all comes from the same pile.
We have 3 types of packs that come with a variety of sizes: