How WebAssign is currently handling grades
At present the exam is NOT included in overall grade calculation in WebAssign, even if you've already taken the final exam. By this weekend, all those who have taken the final exam will be able to see within WebAssign an accurate reflection of your final average in the class. Except in very unusual cases, this will tell you what your final grade for the course will be.
However, for those who are delaying the exam until Monday of next week, the grade displayed by WebAssign over the weekend will be lacking an exam grade. So pay no attention to it until you've completed the exam next week.