What sort of scan's do you mean?
The On access scan (the one that's always running and scans files as they are loaded/written to disk)
The on demand scan, the one you generally run out of business hours and scans all files on systems.
I believe the on-demand is a bit random but ultimately you want everything scanned to ensure nothing has got on your end points.
whats the issue you are facing?
The ODS scanning in MOVE AV is designed to prevent AV Storms caused by ODS Scans. First, the ODS scan leverages the Global Cache, and does not have to re-scan files that have recently been accessed and scanned by the On-Access Scanner. As the scanning is performed at the offload server, and clients connected to multiple hypervisors connect to the OSS, it is not possible to monitor the load directly on each hypervisor or data store, therefore, the policy limits the number of concurrent scans. In this way, we prevent overloading.