These are the two that jump out at me. Especially with cdA on a windy course, since aerodynamic drag is proportional to the square of velocity, that begins to have a bigger actual impact on your predicted speed when you’re in nasty wind if your cdA is off. (BBS with 0 wind would be closer given error in your cdA than for an event with lots of wind). The Crr is also suspect.
Overall though it sounds like quite the nightmare 