My Ebony Bow was at first showing 78 damage - but when I look at the damage it does when I'm about to smith, it says 28 or somewhere in the twenties. After a few minutes, it then says 78 again. I'm not sure what actually happened, but this happens every time I smith.
The 28 damage is the raw base damage of that type of weapon. When you see 78 after smithing, that's including all smithing and one/two/archery, etc damage perks added.