FYI Unfortunately, i can't provide a detailed response. Next time please provide us with sample data and code, so we can provide a detailed example.
Thanks for the question, as you stated you were able to get it to work with INTNX. So, I would not have any other suggestions for you.
You provided one line of code, so even if we would use other functions to get the same results it won’t make any difference in your program. Your solution seems good and it's working so I would just leave it as is.
If you are concerned with improving the program code and analyzing how you can improve the run time length. I would highly recommend taking more Advanced SAS training. In this case, I would suggest a SAS Programming 3 course.