No....
A per seat basis means you buy as many seats as you have SEDs OR TPMs to manage. Of course ERAS manages and is bound to the spezific hardware device (from a technical point of view), but it is my understanding that if a customer has bought 100 seats the ERAS is LIMITED to manage 100 devices (SED, TPM, USB SED), regardless what devices are managed. If you buy a new machine you have to take ownership of the new SED in ERAS and delete the old SED of the old machine.
BR
ISPRO