Okay, so Sonny moves Vito to the mall in February. Do we suppose that that February is about 3 months after Vito is shot or is it 14 months (February 1947) after Vito is shot? I choose 3 months. Otherwise, we are to also suppose that Vito lay in bed for over a year until forced to rise from it after Sonny's death. That seems implausible. So, 3 months later is February, 1946. Or, are we to further suppose that all of 1946 went by and some large portion of 1947 ("The war of 1947 ...") before Sonny was murdered and Vito rose from his sick bed? That also seems implausible ("They lost a lot of dough the last few months ..." is Tom's comment to Sonny about the other families and his receiving the cold shoulder on negotiations to end the war).

Sonny was murdered in 1946 and the Don's meeting took place soon thereafter. By summer. Thus, Michael returned in 1947 giving him plenty of time to learn the family business and plan his revenge. I've always maitained that it is near preposterous to suppose that Vito and Michael waited seven years (until 1955) to avenge the family.