Hello Kama ~ ASA is definitely going to require some higher level jobs to complete. The areas you need to go into and gather items are higher level, with stuff still aggro at 90-95. With most missions lines, as long as you have a good LS, and you run the CS and prep work, getting help for the battles themselves isn't too difficult. Typically I only see reservations about running missions when people don't take the time to look up where they need to go and get the CS done ahead of time.
Best of luck to you, as this was a fun add-on. I just finished the 2nd to last fight last night and have enjoyed it tremendously.
99 BLM WHM RDM SCH SMN BRD THF DNC WAR
~~Remember the Titans~~