I just noticed my zx2 auto/90k on it was 1/2 qt off the full mark. I used moble 1 EP 5w 30 and a motor crap fl 2005 filter. I have used M1 sense I got the car at 73 k and never had this show up. I run it hard though 6K rpm shifts daily-but I though the moble one would take care of that.
Dustin

 

run a compression test to see how the rings are it may seep some oil past on the high rpm shifts and that is probly why your losing oil