Set-ItemProperty sets Registry Value as String on some systems instead of DWord, why?
I don't have an answer to why it happens but to avoid such instances, be explicit. Use the Type (dynamic) Parameter and specify a RegistryValueKind value (you can also use it with New-ItemProperty) :
Set-ItemProperty -Path HKCR:\Software\MyCompany -Name Level -Value 5 -Type DWord
Try this.
[Microsoft.Win32.Registry]::SetValue("HKEY_CLASSES_ROOT\Software\MyCompany","Level",5,[Microsoft.Win32.RegistryValueKind]::DWord)