Soups has been a bit of a discussion lately as far as how long they need to be processed. The Ball Blue Book says they go 75 minutes for pints and 90 minutes for quarts while The National Center for Home Food Preservation recommends that soups be processed 60 minutes for pints and 75 minutes for quarts.
From what I can determine, the reason for this difference in processing times is the amount of solids vs liquids in the jars.
Ball's recipes just tell you to fill your jars leaving one inch head space while NCFHFP says to fill with 1/2 solids and 1/2 liquids. I believe that is the reason for the difference in processing times. You should follow the directions for the recipe you are using since they are both safe canning guides. I am posting a link to both sites FYI.
This layered Beef Stew is full of solids and I just add the liquid over it. This is processed for 90 minutes. If I made the same stew in a pot and then only filled my jars half full with solids and then covered them with the broth, then I would only process it for 75 minutes.