I'm assuming the cpanel samples over a longer length of time. If you use top, or sar, you'll can exact measurements from the kernel. However, if you ever sit there and watch a process, you will notice it spikes up and down up and down, it never runs at a nominal level. When TCA collects its samples, it more than likely falls on a valley in the graph vs a peak, or its using an average based on a number of samples.
Mono is going to utilize a decent amount of memory, remember its an emulator, so its running a program through a program, thus consuming the memory of the later.
You can use the following commands in *ix to get a better idea of how things have been running:
if you wanted to view the load averages for your server from the 23rd of the month, you would run this command:
[user@host ~]$ sar -q -f /var/log/sa/sa23
(ls -al /var/log/sa/ and see which dates are available, substitte as needed)
Current CPU usage
Run "top", and on the line that says "Cpu(s)", check the "%id" section which shows the percentage of which your CPUs are idle. The higher the number the better. A 99% idle CPU is not doing much of anything, and a 1% idle CPU is heavily tasked.
[user@host ~]$ top c
Tip: hit "P" to sort by processes that are currently consuming the most CPU.
Historical CPU usage
Check the "%idle" column:
[user@host ~]$ sar -p
Current memory usage:
[user@host ~]$ free -m
Tip: run "top c" and hit "M" to see which processes are consuming the most memory.
Historical memory usage
This depends on the version of sar, which used to use '-r' to show %memused and %swpused (swap memory used), but later changed to '-S' to show %swpused.
Check "%memused" and "%swpused":
[user@host ~]$ sar -r
Hope that helps