Rerunning a loop with a condition.

This is a small part of my loop which gives me the value of P.M in the end;  which is a

(312 X 10) matrix.

I am interested in calculating P.M with a condition saying (PM<x) it reruns the loop again

incresing the value of xi by 10 each time

Please ignore the error as i have deleated 95% of the table since it was 15 pages long.

If  someone could please write a discription or a short example for help.

thanks in advance.