MOB is nothing more than a "visual debugging" interface to underlying vSphere API ... whats more important to understand IS the vSphere API and its modeling and inventory structure, so you can navigate it and the MOB can help but if you don't understand how API actually works, then simply browsing the MOB won't help either 
As I've already shared in my previous reply, the API reference gives you all the info you need. The RefreshServices() method is available under HostServiceSystem managed object, which you will need to retrieve for the given ESXi host before you can all it
Here's is PowerCLI way of interacting with vSphere API and obtaining a reference to ServiceSystem and then calling the method
$ss = Get-View (Get-VMHost 192.168.30.5).ExtensionData.ConfigManager.ServiceSystem
$ss.RefreshServices()