SOA "minimum" vs "negative ttl"

[Jack Tavares]

I believe that RFC 2308 redefines the SOA "minimum" field to be
"negative ttl"

If I create a dynamically updated zone file that looks like so:

[begin]
$ORIGIN .
$TTL 500
new.com IN SOA d62.test.com. hostmaster.d62.test.com. 2013012301 10800 3600  604800 86400
new.com IN NS d62.test.com.
[end]

When a DNS update comes into to add or modify a record and bind eventually re-writes
the master file it will rearrange the SOA and add comments (which is fine) but it labels
the last field as "minimum"

[begin]
$ORIGIN .
$TTL 500	; 8 minutes 20 seconds
new.com			IN SOA	d62.test.com. hostmaster.d62.test.com. (
				2013012302 ; serial
				10800           ; refresh (3 hours)
				3600             ; retry (1 hour)
				604800         ; expire (1 week)
				86400           ; minimum (1 day)
				)
			NS	d62.test.com.
$ORIGIN new.com.
a			A	1.2.3.4
[end]

Is there a reason for this or is it just a hold over?
It is perpetrating a misconception that this is the minimum TTL.

Thanks

--
Jack Tavares