When I was rejected for childhood asthma, I appealed it. I performed the diagnostic testing the RMO required, had a positive outcome and a note from a pulmonary specialist stating he saw no evidence of asthma. I was rejected and stated I need to carry out a different diagnostic test. I did, and was told I could go no further in the test because I reached the maximum and there was clearly no sign of asthma. I sent the results off to the RMO and was rejected again, and again was asked to carry out a third diagnostic test (note that all three were different tests). I did so, and was told - again - absolutely no signs of asthma and that the only put in doing this test further would be to measure my heart rate at varying levels of fitness, which the test was not designed for. I sent this third set of results off and was finally accept.
Now given that the RMO rejected me on the basis of childhood exercise induced asthma, could they have just skipped the first two tests and had me take the last test, the one for exercise induced asthma? Sure. But they didn't. Could they have sent me a single note telling me to complete all three tests and then send them the results all in one go? Sure. But they didn't. And they had there reasons, which I can only speculate on.
Now keep in mind this is specific to my case, so your case may be different.
1) The initial test was a pulmonary function test. By doing this test first and sending the results in before anything else, they confirmed my lungs were functioning properly and my past asthma was not a result of poor lung function.
2) The second test was a methacholine challenge. My lungs work properly, now they want to rule out environmental factors.
3) Having ruled out environmental factors, now they can say for sure that my past asthma was exercise induced and have me do the exercise test to rule it out.
Yes, all three could have be done and then the results sent in. But if I failed the first or second test, why waste my time with the third. And if they only had my exercise test, what would happen if I ended up having an asthma attack while working when I hadn't been exercising?
As well, the fact I followed what they said and didn't just call it quits because they rejected me and made me appeal again with another test shows that I was determined to follow through and was capable of understanding what I being asked to do...important things when going through BMQ.
I can't speak to your individual case but yes, you may get multiple rejection letters with new instructions on how to appeal each time. If you truly believe you can be accepted and are prepared to back it up with professional medical evidence, then follow along with what they ask of you.