I did not for a second think that it was you. MIR's calculation is valid, though, IMO. Here's why:
The sum of all probabilities of a particular outcome is 1. For example, if there is 50% chance of rain that is .5 and a 50% chance of no rain that is .5. Together they total 1.
When you want to see what the chances are that something will happen over multiple opportunities, you take all the chances that it won't happen and multiply them together. You subtract that figure from 1. That is the chance that something will happen at least once during a given time frame.
For example, let's say that we flip a coin three times and we want at least one head. One head, two heads, or three heads would all be okay (in any order). So they only thing that we DON'T want is all tails. The probability of a tail flip is 1/2, so the probability of all tails is 1/2*1/2*1/2 or (1/2) to the third power, which is 1/8. Thus, the chance of at least one head is 1 - 1/8 or 7/8. You can even write out the scenarios and see that there are eight possible and seven include at least one head.
In this case, if you try for twelve months the only thing you DON"T want is to fail all twelve months. I believe MIR's number was something like 17% succeed monthly, or 83% fail (something like that). Thus, if you try mini IVF for twelve months, your chances of success are 1 - (.83)^12th power.
Admittedly, this is an imperfect calculation. You can't just cycle 1000 times; after about 44 your chances drop so much that you can't include those cycles. A 40 year-old will have a better chance than a 44 year-old. But this is the data MIR had for the 40-44 age group.
I hope that this helps clears up why I DO believe that this is a valid calculation. And I hope that everyone can see that some people will never succeed with this calculation . . . it will approach but never reach 1.