When the WINSORIZED=value(s) option is specified in the PROC CAPABILITY statement, a different value than the one specified might be used to compute the Winsorized means. For example, if you request a 20% Winsorized mean with WINSORIZED=0.20, a 30% winsorized mean is computed instead. The output will indicate the value that is used.

There is no circumvention for this problem.