It wasn't 1 quart in 1000 miles?My GS350 burned a quart in 300 miles on the highway at one point. It took two Valvoline Restore and Protect changes of 5K each to take it back to not burning at all. I didn't feel any change in power generation.
On my GS350, it went from about 1K miles / quart to no burning in less than two oil changes of 5K each. I posted about it in this thread in case you're interested in its progression.