I don't know for sure if this reflects PERS, but my take-away from the bottom bar graph is that Oregon, as you said, spends a total amount per student that is middle of the pack. But, as the dark blue bar shows, it is very near the bottom for instructional salaries. However, it is middle of the pack again when combining instructional salaries and instructional benefits. This demonstrates that the benefits are higher than most. My impression is that the PERS charge gets accounted for under benefits, as it is part of contributing to the retirement plan. 

If the high benefits cost is due to PERS, then a reasonable conclusion would be that right now we pay very little, comparatively, for instructional salaries, but with a typical benefits cost we could pay more and have middle of the pack results to go along with middle of the pack costs.