Depending on which part of the world you are located (e.g., EU) LO flow does not comply with the fresh air circulation regulations, hence the Airbus PAX information in the FCOM.
ATB
Well, I am in India, so I highly doubt there is any regulation for fresh air circulation. Yes, I am worried about the pax but more than that I am worried about myself, four sectors a day with almost all flights full; So seven hours in the tube with pack flow to LO worries me a little.
I have written an email to ops dept, will let you know of the results/answer.