Probably too late for Ken but I just changed the line: if (($Policy.PolicyCategory -eq $PolicyCategoryFilter) -or ($PolicyCategoryFilter -eq ""))
to: if (($Policy.PolicyCategory -eq $PolicyCategoryFilter)-or ($PolicyCategoryFilter -eq "") -and ($Policy.CategoryId -gt 8) -and ($Policy.CategoryId -ne 15))
as the Availabilty policies are all in categories 1-8 and 15 is the windows log file. This came from select * from msdb..syspolicy_policy_categories
to: if (($Policy.PolicyCategory -eq $PolicyCategoryFilter)-or ($PolicyCategoryFilter -eq "") -and ($Policy.CategoryId -gt 8) -and ($Policy.CategoryId -ne 15))
as the Availabilty policies are all in categories 1-8 and 15 is the windows log file. This came from select * from msdb..syspolicy_policy_categories