The following experience might be of some relevance to this very interesting and informative thread.
I did my Nitrox Certification yesterday. I have been planning to do it for the past one month. In that process, I have been reading up on ScubaBoard, have downloaded tons of material from the internet and have generally been preparing myself. I will describe the entire process of the instruction that I received. I do not want to name the resort or the Certifying Agency.
I called the resort on Wednesday and said I wanted to take the Nitrox Course. I was asked to come the same evening to collect the course material and that I could do the course on Thursday. I collected the material Wednesday evening 6 p.m. Luckily since I had been doing a lot of reading on Nitrox independently I was able to complete the knowledge reviews without even having to read the material.
Thursday morning I was at the resort at 8.45 a.m. My gear was hauled to the boat, I was shown 2 nitrox cylinders, the instructor came to me with a hand-held device, said it was an oxygen analyser, asked me to press one button, showed me a reading of 21.8%, said it was calibrated, asked me to slightly crank open the cylinder valve hold the analyser's mouth (or nose?) against the valve for some time and check the reading.
The forrmula for calculating MOD is stuck on the wall beside the stack of Nitrox cylinders. He gave me a calculator and asked me to use the formula. Then tore off some sticky tape and asked me to write the FO2, MOD and PO2 and my name on the tape and stuck it on the cylinders. We then went out to the boat. This whole process took 5 - 10 minutes. No briefing, no explanation, nothing. We went out and did two dives. There was a divemaster and four more divers ( not students). The instructor followed us around (hopefully keeping a watchful eye for signs of CNS oxygen toxicity). No discussion between the dives, no questions, nothing.
We came back to shore had lunch and then on to the theory portion. I was made to watch a 20 minute video that was essentially a summary of what was available in the course material. The knowledge reviews that I had completed were evaluated by an instructor ( a different one, the instructor who dived with me had gone on an afternoon session. I did not see him briefing this other instructor on any aspects of the two dives that I did). After the review I was given two sheets of papers with questions and multiple choice answers. No briefing on the tables to be used, how to use them, nothing. Fortunately I had given myself a strong base by doing a lot of reading over the past month and was able to answer all the questions correctly. The second instructor came back and checked my answers against an answer evaluation sheet that he had. Tick, Tick, Tick, Tick. He marked two mistakes. One of them I was able to prove that his master evaluation sheet was wrong. The other was a question on CNS clock exposure and I, instead of using this particular training agency's table had used the formula for calculating PO2 and there was a 1% difference in my answer.
This instructor seemed a little confused whe I calculated the PO2 and then showed me a statement at the top of the question paper which basically said that I was suposed to use ONLY the agency's tables for calculations and not my intelligence or knowledge.
I accepted my mistake in trying to use my brains, my answers were scored and CONGRATS I was certified. I paid out the money and got my Nitrox C-Card on the spot and was encouraged to take the Advanced Nitrox Course. When I asked what new stuff I would be taught in the advanced class, I was told that I would learn to use EAN upto 100%. When I said that after all wasn't it only a case of applying Dalton's Law whether EAN22 or EAN100, I received no clear answers. I thanked everybody for the course and for the card and am now a Nitrox Certified Recreational Diver.
Edit:
Oh yes I forgot to mention that I was fortunate enough to be taken around the resort's nitrox blending facility for 5 whole minutes and shown the mixing panel.
