I'd say it's just fine.
The LT/KFX's are jetted fat. Yes you could go to a 90 main jet w/o problem but jet size has nothing to do with the amount of oil burnt.
If there is a downside to it smoking, it would be that the pipe will plug up faster.it'll still take a year or 2 to effect it much.
Possibly a different kind of oil someday. I like synthetics.