Well, it's doing something that isn't built into the rules of the game, so in that sense, yes, it's cheating.
But on the other hand, it isn't getting something you wouldn't ordinarily have access to, and it sounds like you're mostly just doing it so you don't have to slog back to town every hour or so to buy more arrows. It doesn't sound like it's affecting the challenge of the game, and it's improving your enjoyment of it. So in that sense, if you're looking for some kind of blessing, I'd say go for it. Single-player games are for your enjoyment; do what you want to make them enjoyable. Just be kind enough not to loudly compare your experience with others' if it comes up- if you come back later and say, for example, that Oblivion is way too easy (which may have been because you were able to specialize in Archery in a way the creators never intended), that would be less than kosher.
