Host Hardware Sensors stale data through PowerCLI

I'm trying to read the temperature values available on the hardware status tab on our hosts via PowerCLI:

Get-VMHost | Sort | % {
    $reading = ((Get-View $_.id).Runtime.HealthSystemRuntime.SystemHealthInfo.NumericSensorInfo | ? {$_.Name -like "*External Environment*"}).CurrentReading
    Write "$_`t$reading"
}

host1   2100
host2   2300
[...]

The values are usually off by a few degrees if I compare them to the values displayed on the ILO website of the host or the hardware status tab in the vSphere Client (which are matching up).

I tried refreshing sensors manually in the Client and executing:

(Get-View (Get-VMHost -Name host1 | Get-View).ConfigManager.HealthStatusSystem).ResetSystemHealthInfo()

(Get-View (Get-VMHost -Name host1 | Get-View).ConfigManager.HealthStatusSystem).UpdateViewData()

(Get-View (Get-VMHost -Name host1 | Get-View).ConfigManager.HealthStatusSystem).RefreshHealthStatusSystem()

as suggested by http://kb.vmware.com/kb/1037330, but I still get old (or incorrect?) values when querying the temperature like above through PowerCLI

Using ESXi 5.0 U1 and PowerCLI 5.0.1 build 581491.