I was thinking about starting a 24 hour race and I have a question. Say for arguments sake the total distance covered over the 24 hours is 2000 miles. Say if I was planning on doing the first 12 hours (1000 miles) on A-Spec and then the rest on B-Spec. Would I have an increase of 1000 miles to both my A-Spec mileage and B-Spec mileage or would I have an increase of 2000 miles to my B-Spec mileage?