Issue adding PowerShell custom sensor values

Hi,

We seem to be having an adding a custom powershell sensor to PRTG. The sensor accept literals within values on the sensor, however when I use variables within the script it returns 0 instead of a value.

Please see the script and sample output below

Script

$Query = "
SET NOCOUNT ON;
IF OBJECT_ID('TempDB..#tokens','U') IS NOT NULL DROP TABLE #tokens;
IF OBJECT_ID('TempDB..#TokenOutput','U') IS NOT NULL DROP TABLE #TokenOutput;
DECLARE 
       @publication sysname
       ,@tokenID AS INT
       ,@StartTime DATETIME = GETDATE();
SET @publication = N'TRN-WLRCRM'; 

EXEC sys.sp_posttracertoken 
  @publication = @publication,
  @tracer_token_id = @tokenID OUTPUT;



WAITFOR DELAY '00:00:2';


CREATE TABLE #tokens (tracer_id int, publisher_commit datetime);

INSERT #tokens (tracer_id, publisher_commit)
EXEC sys.sp_helptracertokens @publication = @publication;
SET @tokenID = (SELECT TOP 1 tracer_id FROM #tokens
ORDER BY publisher_commit DESC);


CREATE TABLE #TokenOutput (ID INT IDENTITY(1,1),  [distributor_latency] int, [subscriber] nvarchar(128), [subscriber_db] nvarchar(128), [subscriber_latency] int, [overall_latency] int  );

WHILE 1 = 1
BEGIN
       WAITFOR DELAY '00:00:01';  
       INSERT INTO #TokenOutput
       EXEC sys.sp_helptracertokenhistory 
         @publication = @publication, 
         @tracer_id = @tokenID;
       IF EXISTS (SELECT TOP 1 1 FROM #TokenOutput WHERE  overall_latency IS NULL)
              BEGIN
                     IF DATEDIFF(SECOND,@StartTime,GETDATE()) > 60
                           BEGIN
                                  UPDATE #TokenOutput SET overall_latency = 99 WHERE overall_latency IS NULL;
                           END
                     ELSE
                           BEGIN
                                  DELETE FROM #TokenOutput WHERE overall_latency IS NULL;
                           END
              END
       IF (SELECT COUNT(DISTINCT subscriber) FROM #TokenOutput WHERE  overall_latency IS NOT NULL) = 2
              BEGIN
                     BREAK;
              END
END    

SELECT DISTINCT
       CASE subscriber WHEN 'REP-01' THEN 1 WHEN 'Server2' THEN 2 END Id
       ,subscriber
       ,overall_latency
FROM 
       #TokenOutput;

"
$Output = Invoke-Sqlcmd -ServerInstance TargetServer -Database WLRCRM -Query $Query -QueryTimeout 65


$Rep01 = $Output |  Where-Object {$_.subscriber -eq "Server1"}|SELECT-Object overall_latency 
$DBS01 = $Output |  Where-Object {$_.subscriber -eq "Server2"}|SELECT-Object overall_latency
$Server1.Value = $Server1.overall_latency
$Server2Value = $Server2overall_latency



Powershell script


Write-Host "<prtg>"
    "<result>"
        "<channel>Server2</channel>"
        "<value>$Server2Value</value>"
     "</result>"
     "<result>"
        "<channel>Server1</channel>"
        "<value>$Server1Value</value>"
     "</result>"
"</prtg>" 


Output
<prtg>
<result>
<channel>Server1</channel>
<value>9</value>
</result>
<result>
<channel>Server2</channel>
<value>7</value>
</result>
</prtg>