I noticed that Neutron API also supports multiple allocation_pools per subnet but it requires using the python api instead of the CLI, please see the following script I created to update a subnet with multiple allocation_pools: http://paste.openstack.org/show/115423/
So instead of disabling it in UI i suggest using the python api to create the subnets which support multiple allocation_pools per subnet.
I noticed that Neutron API also supports multiple allocation_pools per subnet but it requires using the python api instead of the CLI, please see the following script I created to update a subnet with multiple allocation_pools: http:// paste.openstack .org/show/ 115423/
So instead of disabling it in UI i suggest using the python api to create the subnets which support multiple allocation_pools per subnet.