Well, this is my opinion (remember I am a rookie AND stupid).
I say #1 also. My word is just that. I was mowing a yard today matter of fact that I am in the exact same situation. I was getting aggravated, but only for a second. You have to realize that YOU are the one that quoted the price, not the customer. You (I) made the mistake, learn from it, keep your word, adjust next year.
On the other end of the spectrum: I had a customer that had a fenced in back yard. I had to push the entire rear. Quoted $55/cut. About mid-season, she had the fence removed. I lowered the price to $45/cut. Did I have to? No. Was I stupid to? Maybe. This is in a Million+ neighborhood, so she could afford it. Does that matter to me? Nope. I do what I think is fair to me and the customer. That way, no regrets (to me).