Flying consultant....Ok, lets try it this way....an 8 hour flight, is 20 mins before landing really that early??? a couple of hundred passengers need to be checked, galleys need to be cleared and secured, bags need to be placed into over heads and floors checked that there are not bits and bops that could cause people to slip, headsets (depending on airline) needed to be collected, toilets need to be checked and then the crew need to be in their seats generally 10 to 5 mins before landing....Thats why we do it at 20mins before hand...beleive me, its the most rushed part of the flight! Id prefer if we did it at 30 mins on a full 747 or 777!!!