If you want them to be sorted like a number, convert the values to number or integer before comparing.

Code:
        Function SortSuiteSizes stJSArticleAttributeInfo attributes1 stJSArticleAttributeInfo attributes2 Returns Integer
            If (Integer(attributes1.Value) > Integer(attributes2.Value)) ;
                Function_Return (GT) 
            If (Integer(attributes1.Value) < Integer(attributes2.Value)) ;
                Function_Return (LT) 
            
            Function_Return (EQ)
        End_Function