Blue,
With respect if you are working 'a lot more than 13 days' for 'around 68 hours' then, honestly, you're stuffing up. I might have mis-read but it doesn't sound like you've been on the A/C long (it also sounds like you're the type who can't be told, but maybe that's just me) I've been around a while and I can only think of a few times I had density less than 5 and they were all because I had stuffed up or something weird was happening with the patterns. Maybe you should ask those 'original shorthaul captains' how to bid and you will get better results.