You have setup Single Use Rate (price for 1 guest) in myallocator for booking.com but it's not sent to booking.com
If at the moment of first mapping property does not have single rates enabled on booking.com side then myallocator saves it into property configuration for booking.com (this can be seen by myallocator development team only) and myallocator excludes Single Use Rates when sending updates to booking.com.
Even if you enable Single Use Rates on booking.com after mapping it on myallocator - myallocator does not detect it and will not start sending Single Use Rate to booking.com
Please contact our Support team at email@example.com asking to start sending Single Use Rate.
Our support team will escalate the request to development team to resolve the issue: the process is manual and may take few days