"But I won't do that" (consultant work edition)

How do I handle my job when I *know* I will not meet my performance target? I'm a consultant with a target utilization rate. It is a key performance metric that impacts our yearly bonus. Sadly, PTO counts against it. I am not going to meet this target , unless I start obscenely overcharging hours (stupid and unethical) or working *a lot* more hours (not an option if I want to be healthy and sane.)

So, start looking for a new job now? Coast until I get written up/reprimanded? File for FMLA/ADA since I do have some legitimate medical issues that make work difficult (depression, occasionally needing PT)? Would love any words of advice or hope here...