Powershell & XML: how to count specific elements for each node

Here is another one for my server for PC Game - Space Engineers. The answer to this question seems simple, but it got stuck as I cannot find the correct way to call this information.

What I would like to do is count the number of times a certain element appears in each node. This partially works for me, but not exactly what I want.

Here's what I have so far:

Excerpt from XML (nodes stacked except for target node)

<MyObjectBuilder_Sector xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <Position>
  <SectorEvents>
  <AppVersion>
  <SectorObjects>
     <MyObjectBuilder_EntityBase xsi:type="MyObjectBuilder_CubeGrid">
        <CubeBlocks>
           <MyObjectBuilder_CubeBlock xsi:type="MyObjectBuilder_Reactor">
           <MyObjectBuilder_CubeBlock xsi:type="MyObjectBuilder_Thrust">
           <MyObjectBuilder_CubeBlock xsi:type="MyObjectBuilder_Drill">
           <MyObjectBuilder_CubeBlock xsi:type="MyObjectBuilder_Drill">
              <SubtypeName>SmallBlockDrill</SubtypeName>
              <EntityId>72280681079646079</EntityId>
              <Min x="1" y="1" z="-7" />
              <BlockOrientation Forward="Forward" Up="Left" />
              <ColorMaskHSV x="0" y="-1" z="0" />
              <Owner>144256542526969420</Owner>
              <ShareMode>None</ShareMode>
              <ShowOnHUD>false</ShowOnHUD>
              <Enabled>false</Enabled>
              <Inventory>
                <Items />
                <nextItemId>0</nextItemId>
              </Inventory>
           </MyObjectBuilder_CubeBlock>

      

        
        
        
      

    

and my powershell code that returns me the number of cube blocks by

<MyObjectBuilder_EntityBase xsi:type="MyObjectBuilder_CubeGrid">

      

        
        
        
      

    

cube mesh.

$filePath = 'F:\DedicatedServer\DataDir\SE Survival 2\Saves\VPS RC 1\SANDBOX_0_0_0_.sbs'
[xml]$myXML = Get-Content $filePath
$ns = New-Object System.Xml.XmlNamespaceManager($myXML.NameTable)
$ns.AddNamespace("xsi", "http://www.w3.org/2001/XMLSchema-instance")

$infos = $myXML.SelectNodes("//SectorObjects/MyObjectBuilder_EntityBase[(@xsi:type='MyObjectBuilder_CubeGrid')]" ,$ns)

foreach ($info in $infos ){

        $info.CubeBlocks.MyObjectBuilder_CubeBlock.count 
}

      

        
        
        
      

    

So I'm trying to get this to get the number of small drills back to a cubic grid. here in XML

<MyObjectBuilder_CubeBlock xsi:type="MyObjectBuilder_Drill">
      <SubtypeName>SmallBlockDrill</SubtypeName>

      

        
        
        
      

    

It seems to me like this is close to a solution, but it returns the same number for each grid of the cube, so it may not be correct.

$info = $info.SelectNodes("//CubeBlocks/MyObjectBuilder_CubeBlock[(@xsi:type='MyObjectBuilder_Drill')]/SubtypeName['SmallBlockDrill']" ,$ns).InnerText
$info.count

      

        
        
        
      

    

The results are below. I believe this is the total number of both large and small exercises in the world that are repeated only for each mesh found. feels close, but I bet that choosing a subtype value does not work the way I want.

490
490
490
490
490
490
490
490