AvgIOPSTotal in Orion.VIM.VMStatistics is null

Hi

I have hit a bit of an issue working with the RESTful API.  Currently I am attempting to perfrom a call that will return the last hour of CPU, Memory and total IOPS for a VM monitored in Orion VMM.

I have an example call set up which returns data

https://(IP of Orion server):17778/SolarWinds/InformationService/v3/Json/Query?query=SELECT+VirtualMachineID,+DateTime,+AvgCPULoad…

This works fine to return everything apart from the AvgIOPSTotal which comes back as null. and is the same for all VMs that I try.

I have checked the loging level in VMware as I am aware that can be an issue post vSphere 5.1 and that is all fine.  Also in the VMM console I can see the IOPS history chart and it has data.  I just cannot see why the data would not be returned via the API.

Any suggestions for what this might be would be appreciated.