I've got a Tenzing TZ6000 and I love the pack until I get over 25 pounds in it. It seems to put all the weight to my shoulders and not to the waist belt. Am I doing something wrong as far as torso adjustment, waist belt position, load lifters, etc.? I feel like it should be able to handle that weight better. Any insight is much appreciated as I don't have much experience in backcountry packs.