Every figure in the table starts from the lowest buyout listed for that material on the realm you picked. Multiply it by how much of the material you gather per hour and you get the subtotal beside it; add the subtotals and you get the total at the bottom. That total is what the listings say your route is worth — not what you are guaranteed to receive. An auction still has to sell, the deposit is yours to lose, and posting a large stack usually pushes the price down against you.
The amount-per-hour column is the part only you can measure. Run a route you know, watch the clock, and enter what you came back with; a rough count from one circuit beats a number copied from someone else’s server. Mining, herbalism and skinning each reward a different mix of items, so the same route can pay very differently depending on which nodes it passes. Once those amounts are yours, the table re-prices the same route later without you measuring again.
Prices are per realm, and every realm is its own market: a stack that clears quickly on one can sit unsold on another, so a total from a friend’s server says little about yours. Two habits make this table more useful than a single reading — compare the same route on a few separate visits before deciding what it is worth, and open a material’s item page to read its price history instead of judging it from one snapshot. The export and copy buttons above hand the same list to Auctionator or TSM for shopping in game.