Are you running sp_sysmon every minute??? If so - STOP!!!. sp_sysmon shares some of the same counters with MDA and clears them (actually it shouldn't by default - but if you are running with clear option, it will) - which impacts MDA data such as monEngine.
Global variables are per connection - not really usable for this. You really want to use monEngine and/or monThread. monThread is the basis for monEngine and tracks CPU usage in ticks - which can be divided from totals to get CPU %.
SAPTOOLS data collection is set up by ATM - no need for DBACockpit for it - HOWEVER, DBACockpit is the *best* place to start for SAP on ASE. It reports a lot of the MDA data in a context that is best for SAP applications - especially for statement cache and query performance stuff. Not sure why you are not using it and then struggling with sp_sysmon.....it is kinda like ignoring an airplane and trying to fly by flapping two big cardboard wings. 