I can confirm the inlet flap / starter was a technique shown and agreed upon at my operator for the -3/4/500
Upon change to AB at 2005 no such trickery needed. ECB what comtrols the sequence, innit? MSN 960 and above (older, leased ships).
What's the problem with trusting your MX AB representative, APU supplier support team and the FCOM guidance? Serious qusestion, there seem to be one.