Text Dimension values will be sorted according to their alphabetical order.
But from the help of load script help.
Order by is a clause used for sorting the records of a resident table before they are processed by the load statement. The resident table can be sorted by one or more fields in ascending or descending order. The sorting is made primarily by numeric value and secondarily by national ASCII value. This clause may only be used when the data source is a resident table. The ordering fields specify which fields the resident table is sorted by. The field can be specified by its name or by its number in the resident table (the first field is number 1).
I have try on load script but It is not sort by ASCII. Should it be a bug?