Parents do you think this is fair?

My step dad grounded me for cheating on my final exam for a month he tends to be a little more strict because he is also the principle of the school and it makes him look bad. My month was almost over I would have been ungrounded the 27th but i decided to try to go outside and speak to my friend that I saw for a few moments. I was trying to figure out if I wanted to gamble my freedom for the summer to chat with a friend outside or just stay inside and wave from the front door. I decided I wanted to take that chance and gamble my freedom but I had to be quick because my step dad went upstairs for a few seconds and so I couldn't go get my shoes and socks because that were upstairs and I didn't want to get caught. My toes barely touched the concrete outside and he was actually outside and that was my brother who went upstairs and not my step dad and I wad busted. Now I'm grounded for an extra week. I don't think it's fair. I do realize that I was gambling my freedom and knew it but come on it wasnt like I stepped outside all the way it was only my toes. I don't think I should be grounded for any longer because my toes were sticking out the front door. he said it was my motives that got me grounded not my toes but I still think it's unfair.