Goldenrivett, my doubt is this:
FCOM States "To determine the single engine gross ceiling, decrease by 1200 ft the result provided by the QRH table".
This gives the impression (at least to me) that what is given in the QRH is the ceiling for twin engine and we need to decrease 1200ft to determine the single engine ceiling, whereas what is given in the QRH is the single engine ceiling.
And the corrections given at the bottom of the chart is for Anti Ice On whereas the checklist in the FCOM states with a precondition (Black Dot)"If Wing A/Ice off ...."
Maybe I am not seeing something which is very obvious. Can someone please clarify.