Policy Statement on Address Space Allocations

InterNIC's error was not in doing what they did to you but in not aligning
the 1st (or at least the 2nd) of those blocks on a RATIONAL boundary (such
as /16) and giving you your CIDR Block from the front end of the range
[reserving the rest for your expansion needs for a designated period of
time (or until they needed to recycle the unused part of the /16 block for
other users)]. Since the InterNIC assigned blocks are not going to be able
to be aggregated anyway, why not just allocate them on large boundaries and
leave room for expansion that will NOT introduce a new announcement when
the ISP comes back for another Block. They can do Garbage Collection when
they run out of the larger CIDR blocks and need to reclaim the "wasted"
space (there is no downside to this method that is worse then the current
system of supplying non-contiguous CIDR blocks to the same ISP [as in your
case]). If you ask for a /16 to hold you for 1 or 2 years, then they should
give it to you but only allow you to use the first /21 until it is full and
you can justify expanding it with a /20 or to a /19 (ie: Give you a /19.5
in lieu of the /20 they gave you). If after the 1 or 2 year period is over
and you are only using the first /19, then they can leave the 2nd /19 as an
expansion area and reissue the other 6 /19s for other ISPs.