Thank you for your reply
Point 1 : I understand about the pack cycle and tail pipe fire .
However I wanted to know when FCOM SOP says putting the APU bleed ON just before engine shutdown will minimize odor (because like you said the APU inlet will suck the engine exhaust), how can this odor be prevented if APU Bleed is put ON just before engine shut down . Why will the exhaust fumes (from engine) NOT be ingested by APU if I switch on APU Bleed 10 minutes before engine shut down , I am not understanding this . In short why just before engine shutdown put the APU bleed ON (as it is specifically mentioned in the FCOM SOP - PARKING)
Point2: So you mean if I am on single engine even if i put the crosbleed ON , the packs will still be on HIGH FLOW. Though the FCOM very specifically says when on SINGLE PACKS - only then high flow . So in the case I mentioned , with single engine if I put the crossbleed ON both packs are now working (though from a single bleed source) Does that mean it will still be on High flow?
Point 3: Thank , i have understood now . grateful for your explanation.
Point4b : not able to find this in FCOM , thus asked here