Saturns are infamous for their weak piston rings. They also tend to run hotter head temps than most cars, from what I hear. Combine the two, and you get ... stuck piston rings. Do a search here or on any Saturn board for "Saturn oil consumption" and you'll unearth an ungodly amount of information. The hoops us Saturn owners have jumped through to solve this problem have met with mixed results. While it appears that the move to a thicker viscosity has helped your situation, I hate to say that the consumption will probably creep upward again.
The current favorite solution is a piston soak, usually a variation on the following: pull spark plugs, pour 2-3 ounces of [insert name of favorite solvent here: Marvel Mystery Oil, B-12 Chemtool, BG-44, GM Top-End Cleaner, GM Piston and Ring Cleaner, Seafoam, Lube Control, Neutra 131 ... you get the picture] into each cylinder, let sit for X amount of hours, install spark plugs, change oil and filter, wait until it's very dark and all your neighbors are asleep, start the car and kill many mosquitos with the ensuing smoke for 10 or 15 minutes.
Some have had success with Auto-RX, but I think the rule of thumb seems to be if you're using upwards of 1 quart/1000 miles, Auto-RX may not do a whole lot -- it reduced my consumption, but didn't put the dent in it that several piston soaks did. (Definitely not knocking Auto-RX -- has helped me out in all of my non-Saturn oil burners, and has also stopped a couple seal leaks in my Saturn, but the ring packs on these things are UGLY when they get carboned up.)
And that's what I know about Saturns and oil consumption ...
