When you call an automation instance directly from a button the method is run immediately as a task, rather than having to go through the request and approval stage. As there is no request associated with the task, you don't see an entry in the Requests page in the WebUI.
You could re-write your button method to launch a
$evm.execute('create_automation_request',...) call to then run the method to modify the number of CPUs. It's slightly more long-winded, but you would get a request created.
Hope this helps,