Hi Andrew,
Please read the following tech flash information from KG:
"Starting with One-Off SP22_H1 for OneWorld® Xe/ERP8.0 and One-Off SP1_E1 for EnterpriseOne® 8.9 (formerly ERP9.0), each downloadable One-Off will be a Full Service Pack structure with all foundation code delivered, as opposed to an incremental set of foundation code which is applied to a Full Service Pack. Please see Tech Flash Communication GSSTF-03-0566 for more information regarding this change."
So, the need of reapplying the base service pack, is not there anymore.
Hope this helps.
Yogi