The Financial Management Regulation (FMR) 7000.14-R explicitly explains the establishment and use of Program Elements in Volume 2B Chapter 5 Section 050106.  The question you are asking pertains to broadening PE lines to provide more flexibility.  The program element is the smallest aggregation of resources in the FYDP and the level of control for RDT&E funds as concerns reprogramming.  Currently there is no guidance allowing DOD to create PE lines with the increased flexibility you expressed below.  The other guidance you need to review concerns the fiscal guidance in US Code Title 31 on the Purpose Statute, Bona Fide Need Rule, and Anti-deficiency Act.

I strongly recommend that you speak with Army Financial Management and Comptroller concerning your questions below.