I disagree with you paralegal friend. I think most people don't pay any attention to legalese. They look at it, eyes glaze over, then they look at you and ask "what does this say?" You respond, "I have no idea when you're going to get your refund, but it definitely will be long after Jan 30." May as well just say that in writing to begin with.
Also, I think we tend to box ourselves in when we write in too much detail. It forces us to adhere to rigid policies or puts us in the position of having to explain why the policy doesn't apply in a particular situation. And if we have a client sign something they don't understand and then trot it out when they have questions, it generally upsets them. It doesn't bring clarity - rather it creates distance and decreases trust. Just my 2 cents worth. Your mileage may vary.
Same issue with the amended returns. I didn't say you shouldn't CHARGE $50 when the situation warrants it - I was just suggesting that you preserve some flexibility for yourself by not promising to only charge that amount.