I have been to LCBR every year for the past 4 years. Their usual stated profiles were 110'/45min first dive, 60'/50min second dive, and 60'/60min afternoon dive. My experience has been that those profiles are very flexible if the divers are not jerks about it. I have done several first dives where my dive time was approaching 60 minutes. Of course I wasn't going to 110' and I made sure that we were among the first couple divers into the water and that we either were not the last out, or surfaced within 1-2 mins of the last ones out. Similarly, I have had 70 minute afternoon dives and not been the last out of the water by far. As was stated above, their profiles are generally aimed at getting you back to the resort in time for lunch. So if everybody on the boat is there on time (or preferably 5 minutes early) in the morning, they have the flexibility to be alot more lenient on the profiles. But if the boat is 15 minutes late leaving the dock, you are the last one in the water, you dive for 60 minutes on the first dive, and have the entire boat waiting 10 minutes for you to surface at the end, you will probably hear about it from a DM. Their DMs really are very easy going folks who work their tails off, so if you show them a little respect and play by the rules they need to follow to get the boat back in time for lunch, they are not going to give you trouble about your profiles. You probably won't get away with a 110 minute dive like Bruce, but getting dives of 60-70 minutes is generally not a problem if you are among the first into the water.
---------- Post added October 9th, 2013 at 03:33 PM ----------
Also, I believe the dive profiles are issued as "guidelines" of some sort by the Cayman Watersports Authority. I know the 110' limit on the first dive comes from CWA, but I am not sure how firmly the "guidelines" are enforced or what flexibility the operators have.