I suggest you open a track with SAS Tech Support on this issue. You are using specialist products which are not widely used.
Whether you upgrade in-place or do a new install will depend on many factors. For example is it technically feasible to upgrade in-place and if so how long will the upgrade take? You need to bear in mind that your installation will be out of action during the upgrade. Is it acceptable to be down for this period?
What are the risks that your existing applications no longer work as expected post-upgrade? Do you need to run both installations in parallel for a period to ensure that migrated applications work correctly and give the same results?