Would something like this do what you need? I've annotated it to describe the various steps; to see the intermediate calculations, just uncomment the various comments I've inserted along the way. If you need a complete flexibility on alpha just replace the radio buttons with an edit text box, but I'm guessing you probably really only want a handful of possible alternatives:
style="font-size: 9pt; font-family: "Courier New"; color: black;"> style=""> style="font-size: 9pt; font-family: "Courier New"; color: green;">// This bit extracts which radio button was selected earlier - it's a bit messy, but it works; style="font-size: 9pt; font-family: "Courier New"; color: black;">
Ah... well if so, then the way I'd set about looking for it would be to display the tree structure of the resulting report, and then inspect the tables of numbers that are incorporated into it. The following does that for three such tables:
The only thing I could find (with limited looking) that contains the alpha value is the script that you can save, for example, to the script window. It ought to be possible to get the script as a text string and search for the "Set Alpha Level" piece but I haven't had a chance to try that.