Heads Up,
What we're doing is using computer decompression programs to generate dive profiles. By "personnal", they may be referring to variables within the programs that can be changed to either increase or decrease conservation. Some programs can get very detailed and get into a divers age, water temp, workload, etc. Other programs have a simple conservation factor that can be adjusted by the user to get the desired conservation. Some people may want to deco out more aggressively than others who are older, overweight, not in great physical fitness, diving in cold water, etc.
There are various "formulas", or models, that programs use to calculate profiles. Some are, by design, more conservative (often unnecessarily so) than others. I'm not going to get into all that, as there is plenty of reading you can do that is written by authors who are much more articulate than I in explaning them.
What you are looking for is a program that is proven by technical divers and well known; incorporates custom mixes; calculates deep stops; and is user friendly. Some good and well known programs are Deco Planner (GUE), GAP (free download), Pro Planner, Z Planner (free download), V Planner (free download and VPM model -- my favorite thus far), and Abyss (expensive). Keep in mind, that no program out there has deco figured out to a tee, and a knowledgable diver can add tricks to the profile (without letting the program know about it) to deco out faster and/or safer.
Learn everything you can about VPM, RGBM, deep stops, accelerated deco with high PPO2 mixes, helium (and it's effects on your body), micro bubble theory, and how it all relates to diving. Authors to keep an eye out for are E. Maiken, E. Baker, B. Hamilton, D. Younte, B. Weinke, G. Irvine, and J. Jablonski.
Here's another link.
http://home.adelphia.net/~robworld
Need anything else, just ask.
Mike
PS. Make sure you know what you're doing and have a thorough
understanding of what's going on before doing any of this stuff. It's not hard to learn if you know who to listen to and what to read, but it will killl you if you screw up.