Dear Geoff,
Conditions on the IPv4 address block:
- Only IPv4 address blocks equal to, or larger than, a /24 prefix
may be transferred.
- The address block must be in the range of addresses administered
by APNIC, either as part of a /8 address block assigned by the
IANA to APNIC, or as part of a historically-assigned address
block now administered by APNIC.
- The address block must be allocated or assigned to a current
APNIC account holder.
- The address block will be subject to all current APNIC policies
from the time of transfer. This includes address blocks
previously considered to be "historical".
I believe this proposal will play an important role in next few years.
I think these conditions are not clear that transfer part of address
block is allowed.
For example, an entity that have /16 can transfer /17 to another entity
or entity should transfer whole of /16.