DHCPServer leases IP address to the client in the following order of precedence.
The above shows us clearly that reservation takes the precedence than exclusion. For example, A scope is defined with an reservation and the reserved IPaddress falls within the exclusion range. Still the DHCPServer will lease the IPaddress to the client even though the reserved IPaddress is excluded from the scope.
-RamaSubbu SKDHCP-NAP | Microsoft