Two things, if you're balking at Aldora's prices (and they are high): Are you stuck on staying down as long as humanly possible on every single dive you do? Since Aldora doesn't seem to cut any real price breaks for multiple days of diving, you could always try a different operator for a few days as well and save a few bucks. Everyone should be able to get you Nitrox, if you're willing to endure a not-to-the-limits dive.
And also, most of the better shops will take you to more "advanced" sites, if everyone is willing and able. I've even been with operators who have gone to Barracuda with divers who literally needed their hands held, have been visibly struggling with weighting issues, etc. I wouldn't characterize the "advanced" sites as necessarily better than the mid-octane sites. Sure, we all go to Palancar sites over and over again--they're beautiful. Don't despair if you don't manage to check everything off your list.
But the Al80 thing begs a question and sort of wanders into the territory of dive etiquette. There are plenty of us who can usually do 80-90 minute dives (and perhaps longer) on 80cf tanks, if our computers give us the go-ahead. But I can't think of too many ops we've used that I believe would look kindly on a diver staying down that long, especially if most everyone else has had to or decided to come up after 60-70 minutes. (And I'll admit, if I were on a boat with you, and you decided to stay a long, long time after I'd politely gotten back aboard with over 1300psi still in my tank, I'd personally be simultaneously envying and resenting you.)
For the operator, I think, there are surface intervals to plan for, and often the need to get the boat back with enough time for the DM to eat and off-gas before the afternoon dive. I did once do a nearly-90 minute night dive with our regular 80cf operator, in part because some other guys were staying down too, but we were practically right in front of the hotel on Barracuda, and clearly it was the last dive of the day. I'd never feel comfortable staying that long on a standard morning dive, though I'm certain our regular DM wouldn't yank us out of the water. I asked him once how long we could stay without it being totally irritating, and he diplomatically answered, "Good question."
Are other people having vastly different experiences? I'm usually okay with not staying down until I suck a tank to the dregs, knowing we have many dives behind us and hopefully many ahead. We, too, will be diving with Aldora for the first time this winter (we did use Living Underwater once years ago, before Jeremy was even the owner). We've been happy with our regular operator, but we decided to try something different. I'll be curious to see how it compares.