*: Booking platforms are online travel agencies (OTA's) like booking.com, Expedia, HRS, AirBnb (and many others) which are connected to Cloud-Rooms.
The connection to external channel-managers (like Hotel Link, Hotelspider, Kognitiv/Seekda, Feratel Deskline, DIRS-21, Vioma, SiteMinder and many others) counts like a booking platform, regardless of how many platforms are driven by it.
If you want to connect several accounts on booking platforms, those count as separate platforms.
Any number of platforms and channel managers can be combined.
You have 4 objects and use the external channel-manager "Hotel Link" with booking.com, Expedia and AirBnB in the first object. In the second object, "Hotelspider" is used, also connected to booking.com, Expedia and AirBnB. You want to use Cloud-Rooms with all 4 objects and connect the third and 4th object also with booking.com, Expedia and AirBnB.
In this case you pay the price for 8 booking platforms: 1 each for the first two objects and 3 each for the 3rd and 4th object.