Nested loop append to file - vbscript

Question

I'm using a piece of software called Chronoscan which uses VBScript.
I am attempting to create and append to a file, which in part is successful. However, I am trying to place an argument based on a child table as to whether or not to export the data.
Firstly I am counting the number of records contained in a table named 'batch' (unique id) and looping this against the record number I am assigning variables, within this loop I have another loop which is doing the same for a child table named 'Grid' again assigning variables. I am then writing these variables to the file. Therefore I am writing a value for the number of records held in the child table for each record held in its parent.
What I actually want to do is to argue against the child table and only write records if it meets my argument.
The child table has a field called SkuType which has 3 possible values M, A or NULL.
My argument needs to be if the child table has a value of M write the record else don't, if the child table does not have a value of M in any of its records relating to it parent then only write the first record from the child table and ignore the remainder.
Please see below example of my code, which works fine for exporting ALL records from the child table.
Dim fso
Dim FilePathName
Dim FilePath
Dim NumDocs
Dim numRows
Dim Station
Dim StationDate
Dim StationTime
Dim StationName
Dim Exp
GridPanel = 1 'first panel
Set Batch = ChronoApp.GetCurrentBatch
CurrentBatchname = Batch.Getname
NumDocs = Batch.GetDocCount
'Set output filename and path here
Station = ChronoApp.GetVariableValue("station_user")
StationDate = Left(ChronoApp.GetVariableValue("station_date_full"), 10)
StationName = ChronoApp.GetVariableValue("station_name")
Set fso = CreateObject("Scripting.FileSystemObject")
'Loop the batch here
For numDoc = 0 To NumDocs-1
FilePath = "C:\Users\" & Station & "\Google Drive\Driver Scans\ChronoPlans\" &_
Left(Batch.GetUserField(numDoc, "Movement Date"),2) &_
Mid(Batch.GetUserField(numDoc, "Movement Date"),4,2) &_
Right(Batch.GetUserField(numDoc, "Movement Date"),2) & "\"
FilePathName = FilePath & StationName & "_" & StationDate & ".CSV"
If Not fso.FolderExists(FilePath) Then FSO.CreateFolder (FilePath) 'create folder if it does not exist
Set inputFile = fso.OpenTextFile(FilePathName, 8, True)
'Get header level fields here
StationTime= Left(ChronoApp.GetVariableValue("station_date_full"), 16)
'Loop grid here
numRows = Batch.GetXgridRowCount (numDoc, GridPanel)
For row = 0 To numRows-1
'Get grid level fields here
SkuType = Batch.GetXgridFieldValue (numDoc, GridPanel, row, "SkuType")
'Get Serial
SKU = Batch.GetXgridFieldValue (numDoc, GridPanel, row, "SKU")
'Write to file here
inputFile.WriteLine(_
Chr(34) & SKU & Chr(34) & "," &_
Chr(34) & StationTime & Chr(34)& "," &_
Chr(34) & SkuType & Chr(34) )
Next 'loop Grid
inputFile.Close
Next 'Loop Batch
'Now cleanup
inputFile.Close
Set inputFile = Nothing
Set fso = Nothing