Operator utterance: "dc0 10.12.40.0/22, dc1 10.12.88.0/22 (Recommended)", after asking
for a recommendation matching the existing per-DC pattern. Supersedes 10.12.60.0/22 from
amendment (a), which was ruled back into force before the pattern had been measured.

Measured: the dc0->dc1 offset is a consequence, not a rule. dc0 is 4,8,12,16,[20-28
free],32,36; dc1 is contiguous 64..84; the offset runs +60 x4 then +48 x2 because dc1
never reproduced dc0's historical gap. dc0's gap is unusable for a symmetric pair --
20+60=80 and 20+48=68 are both allocated. 40 and 88 are each the next free /22 after
their own DC's highest plane, keeping both runs contiguous at the +48 offset storage
and replication already use.

10.12.60.0/22 returns to the free pool; D-058 stays superseded in full. The v6 half is
built for dc0; the v4 half is ruled and NOT built and gates nothing.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf