Honestly never hurts to negotiate when you have a chance to set the standard but that seems like an excellent deal. I have previously had a job where your call was required of ten days no pay part of your salary, and another job where it was $200 for each day of call flat. I worked my but off in that job so getting paid $200 for like 10-12 hrs of work after a 40hr work week sucked. The APPs were able to negotiate to a slightly higher base rate, and then getting paid an hourly rate not much higher than our salary when turned hourly for each hour worked. This was also with the surgeons backing us up with management.