I'm not an expertologist on this, but I believe the genetics that give the autoflower trait are from indica/sativa crossed with ruderalis. If you cross two autos I'd make the assumption that the result would also show the autoflower trait.
Yes if you have a male autoflower and a female autoflower and cross and pollinate the female with the male pollen you will have more autoflowering seeds since the father is has autoflowering genetics and the female has autoflowering genetics which is ruderalis.
