No problems at all. Have done on several airlines, and as long as you are going to a third country (so LHR-PVG-MAN would not be permitted, but LHR-PVG-HKG-MAN is fine). And for this purpose Macau and HK are third countries.
May need to check the exact wording of the rules if you are planning to be very close to 144hrs. I think the count actually starts midnight the day after you arrive. So say you arrive day 0 at 3pm then the clock only starts ticking at 00.00 on day 1, which effectively means 144hrs+part of a day.