Yup, DNA is funny... my breakdown shows 11% "Iberian Peninsula", which would correspond to the same amount as one would inherit from a great-grandparent, but I have no recent Spanish or Portuguese ancestry, certainly not 11% worth. But many of my ancestors hail from New Hampshire, and it turns out that there were many Spanish and Portuguese fishermen who settled on the Isle of Shoals, so that might account for part of that. Additionally, Irish/Celtic ancestry can also show up as "Iberian Peninsula", since Celts did settle in that area.