Not seeing all systems in AD Group

[bcaulkins]

I have made a report as follows to try and get all systems in an AD group

Select Top 1000000 tblAssets.AssetID,
  tblAssets.AssetName,
  tsysAssetTypes.AssetTypename,
  tsysAssetTypes.AssetTypeIcon10 As icon,
  tblADComputers.AdcomputerID,
  tblADComputers.OU,
  tblAssetCustom.State
From tblAssets
  Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
  Inner Join tsysAssetTypes On tsysAssetTypes.AssetType = tblAssets.Assettype
  Inner Join tblADComputers On tblAssets.AssetID = tblADComputers.AssetID
Where tblADComputers.OU Like '%clearwater%' And tblADComputers.OU Like
  '%workstations%' And tblAssetCustom.State = 1

This is not find all of the systems. This reports 78 where as the Get-ADComputer powershell command counts 97.
I am seeing systems in AD not in LanSweeper. Now some of these system are older and prolly have not been touched in a while.
Is there a way to get the last of the systems I am missing.