matkat,
Agree with most of what you are saying but there exists now situations where an SB and AMM are both referenced by the MPD.
For the A300 the AMM/MPD/CPCP/SSID are all issued at different times and with SB's being revised outside this there exists conflicts where the SB has different limits to the AMM yet both are mandated by the MPD. Hence why I believe the issue date does take effect. Incidently that was the response received from AI when the question was put to them for a definitive answer.