My point is, Vincent stating that Vito got his start making $3/hour at Genco is not accurate. It should have been worded something like, "That's were it all started for our grandfather." or something similar. To me it is just sloppy writing based on what we know from II.
Right, it's not accurate but I don't think it's sloppy writing or an oversight.
All family histories get a bit of unreality as the generations pass and it seems perfectly natural for Vincent to further the Family mythology about Vito's humble beginnings.
That comment makes more sense than him saying "That's where our grandfather set up a front company after murdering Don Fanucci and taking over his protection rackets."
Also, bear in mind that Vincent wasn't raised in the family so his information probably came from Lucy Mancini, who might not have known the true details of Vito's younger days.
