I found that if Moira could repair your stuff better when she's convinced not to write her book, the advantage of giving her 100 repair skill would ruin the advantage of being an evil jerk.

So I did something a bit more lore friendly (to my tastes anyway)  I gave the guy named Ken Ewers in Arefu 100 repair skill since he will only offer his repair services after the quest that Lucy West in Megaton gave you. 

That's it, really.