I am in the same boat. My impression, at the 10 year mark, is that my salary will continue to decline in terms of WRVU's. I work at about the 85th percentile, not as much as others on this site but hard enough for me.
I am up for renegotiation this year and have asked for my total collections (I Imagine around 2 million) between office and surgery center. I do 80 percent pain (20 percent anesthesia at my request). Look at your salary and see how it compares to a percent of collections. The general rule is close to 40 percent but arguments can be made either way. More importantly when they talk about overhead have them break down what that means. I personal want a line-by-line list of what my "overhead" is in terms of what I am paying for. I won't be taking a decrease. I will be taking a walk before I do that and in fact will be asking for a raise. Remember the only person that is generating money is you, not the admins, etc. Your highly compensated because you generate that money. Your "pay" comes from what YOU generate, not them.