This is the vrops plugin to the web client.
You can only have the plugin active to one vcenter at a time. This has nothing to do with the collection of data from the vcenters.
before you decom your old vrops just go back into the adapters and run through the manage registrations wizzard to remove the oild and add the new
So if you have 25 vcenters that you would like to use the vcenter vrops plugin, you would need 25 vrops instances?
you can have 1 vrops with 25 vcenters registered and all vcenters can have the web plugin
you can have 2 vrops with the same 25 vcenter registered to both but only 1 vrops instence will provide the web pligin on the vcenter. You can have 10 with 1 vrops plugin and 15 with the other but only 1 web plugin can be active at a time