Question about ISP Address Requests

[J Bacher]

>ARIN reviews requests for IPv4 address space in accordance with
>the policies that can be found at
>
>         http://www.arin.net/regserv/initial-isp.html

The multi-homing section defines a required 50% (/21) utilization to obtain 
a /20.

The section preceding multi-homing states: "ARIN allocates IP address 
prefixes no longer than /20. If allocations smaller than /20 are needed, 
ISPs should request address space from their upstream provider."  Is 
"needed" defined "must be able to immediately utilize?"

The policy that defines IP address allocation for single-homed customers 
does not have the clarification as the policy for multi-homed 
customers.  I'm asking for that clarification.

It doesn't justify my calling ARIN's office until I know which of the two 
ARIN employees gave me the wrong answer.