For non-rollup threads TCB-CPU-TOT=(QWACEJST-QWACBJST) +QWACSPCP+QWACUDCP
For rollup threads TCB-CPU-TOT=QWACEJST +QWACSPCP+QWACUDCP
According to IBM Knowledge Center for Tivoli OMEGAMON XE for DB2 Performance Expert on z/OS
CLASS 1: MVS TCB TIME
The amount of MVS CPU time used. If the time cannot be calculated or the value is negative, N/C is printed in this field. Calculated from the DB2 field QWACEJST - QWACBJST.