Multiple Comparison, Difference from Overall Average Adjusted Prob

[#1]

Good Afternoon,

    My question is simple: what is the type of p-value adjustment in "Adjusted Prob" within "Comparison to Overall Average" using the "Mulitple Comparison"?

Details:  Using Fit Model with model effect that has 74 categories (nominal; N ~550), I can get the "Multiple Comparison" using the red-triangle in the Response results.  Within the multiple comparison, I can use the red-triangle to get a "Compare to Overall Average", and using "control" on table add "Adjusted Prob".  I am unsure what the adjustment is?  It is not a Bonferroni's.  
What is it?

Best

Doug

[#2]

When you have the report open which you are interested in, select the Help item "?"  from toolbar and click on the section you wish to know more about. 

Not sure if this is exactly the part of report you are looking for but it might function as an example:

This will generally get you quite close to what you are looking for from JMP Help page,  Fitting Linear Models > Standard Least Squares Models > Multiple Comparisons > Comparisons with Ove... 

[#3]

HI, Thanks.  Unfortunately , the help pages are not specific about the adjustment. 
However, if I would have paid closer attention (see paste), the adjustment is Nelson.  

Now, I am wondering if I can change the adjustment?