Problem getting latest version metadata filter working

I am trying to use the metadata filter below with find-ishDocumentObj in PowerShell and it returns zero docs. If I block the last line that defines the version as 'latest' it works but returns multiple ishmodules. Can someone tell me what I am doing wrong? Does 'latest' not work with a metadata filter? 

 

$metadataFilter =

Set-IshMetadataFilterField -IshSession $ishSession -Name "DOC-LANGUAGE" -Level "Lng" -FilterOperator "equal" -Value "en-US" |

Set-IshMetadataFilterField -IshSession $ishSession -Name "CREATED-ON" -Level "version" -FilterOperator "greaterthan" -Value "14/6/2016 00:00:00" |

Set-IshMetadataFilterField -IshSession $ishSession -Name "CREATED-ON" -Level "version" -FilterOperator "lessthan" -Value "14/12/2017 00:00:00" |

Set-IshMetadataFilterField -IshSession $ishSession -Name "VERSION" -Level "version" -FilterOperator "equal" -Value "latest"