upgrade process from ax 2009 to ax 2012

HI ALL,

i just want to know about the code upgrade process from ax 2009 to ax 2012.

what is the difference,

1) if i imported all customizations through  .xpo file.

2) if i moved customizations through AOD code upgrade check list in ax 2012.

will they both gives the same result? else the AOD code upgrade tool having any other capabilities to resolve the minor conflicts?

can any one explain me the difference?

thanks in advance......