AZORCH, no I don't typically see oversized spokes on factory-spec'd wheels. So thank you for asking, because it makes me realize it could be something else. Perhaps the spec was for spokes that typically aren't tightened quite that much. Maybe there is a bad assumption about how much tension will be put into the wheel. When I build a wheel, I make it absolutely as tight as I can.

Could riding hard create excess tension, if only momentarily? I suppose, but I don't know enough to say so.