I can see the temptation to have your dean or PD give you advice on what to put in your dean's letter, as they are the individuals you are trying to impress. I would not have the PD or chair be the person who you have evaluate/proof your PS and CV unless you have a very close relation to them. You should have a (nearly) finalized copy to present to them when you ask for your LOR. Talk to your academic advisor or someone who has seen and evaluated a lot of PSs.
Do NOT put your Step 1,2, or 3 scores on your CV. IMHO you will look like a boob, even if you did outstanding. During interviews at some institutions, not everyone has full access to all parts of your file, in an attempt to avoid bias during the interview process. Almost every interviewer will have the opportunity to read your PS and CV, so if you put that you scored 220 and they think a quality applicant scores at least 221, you hosed yourself. Likewise if you score higher than their average applicant, they may think that you'll never never go to their program because you have such outstanding marks. Either way, you'll come off looking like a tool by placing your step score in your PS or CV.
