The step 4 heading said "once per DID" and the intro said steps 3-7 repeat
per DID, both of which overstate the work. The body already noted the trunk
could be reused, but the heading is what gets read first - and it actively
misleads toward creating one trunk object per number.
One inbound SIP Trunk serves the whole account: the $[E164]$ placeholder is
substituted with each DID's own number at call time, and the Asterisk side
matches whatever arrives via _X. and resolves it through
pstn-personal-dids.conf. Same for the outbound Service Trunk in step 3,
which the body already flagged as skippable for DIDs 2+.
Rewrites the heading, adds an explicit up-front note on why one suffices,
and corrects the intro to name which steps actually repeat per number.