If you use PRELOADFMT in the CLASS statement, the order for the values of each class variable matches the order that PROC FORMAT uses to store the values of the associated user-defined format.

For example, in the first PICTURE statement, the primary label for 1000 is 1,000 because the format 9,999 is the first external value that is assigned to 1000. The secondary label for 1000 is 1000, ...