Potatoes - how deep?

No idea, but have often wondered about earthing up......why don't we just plant them deeper to achieve the same effect.  I'm not a potato grower but I'm sure those who do will tell me.

I prepare the ground by rotovating, then rake it level, set my lens and place a seed spud about 10’’ apart, then I dig a hole about 8-10’’ deep and put the seed spud in the hole with the main chit facing up. I then fill n the holes and rake over the soil to form a drill, later then i earth up on this. I do think more potatoes grow as you Earth up.