@Persephone that’s an interesting way of coming to the conclusion you did, but I think these two pieces of evidence contradict it (they also come from Sharpo and Airline directly and are more closely sourced to the abilities in question):
The “excess” combat damage is the damage beyond the remaining HP of the thing you attacked.
http://codexcarddb.com/ruling/overpower
I think you need to overpower hp with attack power to deal excess damage, and deathtouch applies after the fact.
Please correct your attack results and redraw your new hand