I'd done something which may help with this but its a much longer script but would give you a lot more flexibility.
Consider creating the CSR manually yourself and then using this with the Get-Certificate command rather than specifying the DNS on the commandline.
Take a look at this GitHub example - Not mine but the closest example I could find of the type of thing I mean - https://gist.github.com/paschott/966f5ae8b1eda5efce874914d95aafd9
I'm doing something similar with OpenSSL to create requests I can use to fire over to DigiCert for creating duplicates from a wildcard and its been working well for my use case. I haven't tried this myself on our Internal PKI but I didn't spot anything which jumps out to make me think this isn't something which might work.