Same Process ID obtained multiple times by different WSF Scripts

Question

I'm using the following code to obtain the current pid of the currently started wsf script:

<script language="VBScript" type="text/vbscript">
<![CDATA[
On Error Resume Next
Err.Clear

    REM Obtain process id

    WScript.Echo "#$% Find Process ID"

    strComputer = "."
    Set objWMIService = GetObject("winmgmts:" _
        & "{impersonationLevel=impersonate}!\\" & strComputer & "\root\cimv2")

    Function CurrProcessId
        Dim oShell, sCmd, oWMI, oChldPrcs, oCols, lOut
        lOut = 0
        Set oShell  = CreateObject("WScript.Shell")
        Set oWMI    = GetObject(_
            "winmgmts:{impersonationLevel=impersonate}!\\.\root\cimv2")
        Randomize
        sCmd = "/K @echo " & Int(Rnd * 3333) * CDbl(Timer) \ 1
        oShell.Run "%comspec% " & sCmd, 0
        WScript.Sleep 100 'For healthier skin, get some sleep
        Set oChldPrcs = oWMI.ExecQuery(_
            "Select * From Win32_Process Where CommandLine Like '%" & sCmd & "'", ,32)
        For Each oCols In oChldPrcs
            lOut = oCols.ProcessId 'get parent
            oCols.Terminate 'process terminated
            Exit For
        Next
        Set oChldPrcs = Nothing
        Set oWMI = Nothing
        Set oShell = Nothing
        CurrProcessId = lOut
    End Function

    WScript.Echo CurrProcessId

    WScript.Echo "#$% Process ID Found"

if  Err.Number <> 0  then   
    ' An exception occurred
    WScript.Echo "Exception:" & vbCrLf &_
        "    Error number: " & Err.Number & vbCrLf &_
        "    Error description: '" & Err.Description & vbCrLf
end if
]]>
</script>

It worked perfectly while I started the wsf scripts sequentially, however when more of them is started "parallelly" something unexpected happends, multiple scripts are obtaining the same Process ID:

10 scripts started
#$% Find Process ID
#$% Find Process ID
#$% Find Process ID
#$% Find Process ID
#$% Find Process ID
#$% Find Process ID
#$% Find Process ID
#$% Find Process ID
#$% Find Process ID
#$% Find Process ID
1472
#$% Process ID Found
6664
#$% Process ID Found
6456
#$% Process ID Found
6456
#$% Process ID Found
test1.wsf exit code 0
test10.wsf exit code 0
test2.wsf exit code 0
test4.wsf exit code 0
6456
#$% Process ID Found
4100
#$% Process ID Found
4100
#$% Process ID Found
4100
#$% Process ID Found
test3.wsf exit code 0
test5.wsf exit code 0
test6.wsf exit code 0
test7.wsf exit code 0
#$% Process ID Found
Exception:
    Error number: -2147217406
    Error description: 'Not found

6540
#$% Process ID Found
test8.wsf exit code 0
test9.wsf exit code 0

Not to mention that randomly I'm getting some garbe as exception.

My questions are the following:

1. How it's possible the Windows obtains the same process id for simultaneously started processes?

2. What causes the exception?

3. I'm not experienced in wsf and the above code is literally a copy paste, am I doing something wrong?