First and foremost, largely disregard what the pamphlet that shipped with your machine stated about which baskets do what. It's somewhat convoluted and kind of confusing. If you received the normal loadout of baskets, you should have one (1) pressurized doubleshot ground filter basket, one (1) unpressurized doubleshot ground filter basket, and one (1) pressurized ESE pod basket (sort of usable for ground coffee, but occasionally a source of frustration when trying to do so). When the pressurized baskets, identified by the presence of the single pinhole at the base (when viewed from the bottom), you don't need signifncant tamping force as the basket takes care of creating the appropriate brew pressure. With the remaining doubleshot basket, identified by the mesh that spans the entire bottom surface, proper tamping is key as it does nothing beyond hold the coffee you wish to brew. The rule of thumb/tradition that you're referring to is best applied to this basket and its contents. You'll likely strive for between 30lbs and 40lbs of tamping pressure on a basket full of the correct espresso-ground coffee.