Running EVPM with account other than VSA

Hi folks,

we have a customer here that wants to use an account to run EVPM other than the Vault Service Account.

I already told him several times that it is not supported but he's very keen on doing it.

I told him to grant the second account all permissions that are granted to the VSA, but it doesn't seem to work.

I didn't want him to run SetEVExchangePermissions.ps1 as I don't know what this script does besides granting permissions.

The customer is running EV 10.0.2 and Exchange 2010.

Is there any way to use any other account for EPVM than the VSA?

Does anyone know background about why you should only use the VSA?

Is the VSA affected by running SetEVExchangePermissions.ps1 for any other account?

Thanks in advance!