VSM USEZOSV1R9RULES(NO|YES): YES causes GETMAIN and STORAGE OBTAIN behavior to be unchanged from its historic behavior. NO causes GETMAIN and STORAGE OBTAIN behavior for user-region private area subpools that are both below and above the line to be implemented. Thus DQEs can be merged where possible. The default is YES to provide a seamless migration. However, IBM recommends that you specify USEZOSV1R9RULES(NO) to obtain a performance benefit for applications with long DQE/FQE chains for user-region private area subpools.
There should be no problem for TPX with either setting for USEZOSV1R9RULES.