You noticed substantially increased CPU consumption after your hardware upgrade to an IBM z/13.
Download APAR RO88567 from support.broadcom.com
There are special installation instructions in the APAR.
CPU consumption rose about 30 percent in one case.
Some CA VISION: Report load modules had internal subroutine calls to subroutines with save areas adjacent to the executable code. This programming technique is no longer supported by IBM mainframes.