Question about 'V' and 'A' flow

Once again, im wondering if a ‘V’ of 40-50 is acceptable? Hes running at 310BFR , 32FF and blood pressure stayes fine but that just seems so low. He actually runs in the 60’s usually but today, while sleeping it’s down to low 40’s.
A’s are 100’s. Thank you for any info on this. (sorry if not in right place for this question)