ISE Medium Deployment with >5 PSN?

[mwenstro]

My customer currently has 2 PAN in HA active/standby, 5 PSN each at different sites, 2500 base, 500 plus, 100 apex. Active endpoints is less than 1200.  Customer wants to deploy 2 additional PSN at 2 different sites. Is there any technical (license, etc.) issue that would prevent having a total of 7 PSN without splitting out PAN into PAN + MNT?  Various docs say that if => 5 PSN that makes it a "Large" deployment which warrants dedicated PAN and MNT nodes, which means they would need to buy 2 additional MNT nodes, for a total of 4. Customer does not want to do this. Please confirm. Note the Cisco Live preso slide. Thanks, Mike

Designing ISE for Scale & High Availability (2017 Berlin)