Basically, the final ending "-어요" is a standard word, and "-에요" is a dialect of 서울(Seoul) of "-어요". For examples, 가다. (to go) 가-시-다 (honorific form of 가다, used with the honorific ending/inffix '-시-' ) 가-시-어요, 가시어요, (the final ending '-어요' is added) 가셔요. (This form is contraction of '가시어요', and this is a standard word) However, the people in Seoul tend to speak it '가세요', not '가셔요'. This form is also granted as a standard word since when the government of Korea admitted it as a standard word in the middle of 1980s. So, both '안녕하셔요' and '안녕하세요' are standard words in Korean now. Consider the past form of them. 안녕하셨어요. (o) 안녕하-시-었-어요. (셨 is shorten form of 시-었) 안녕하셨에요. (x) 안녕하-시-었-에요. (This is wrong)

"-셔요" is exactly the same as "-세요" in meaning or level of politeness, but "-셔요" is often used with the past tense.:) e.g. 말하다 > 말씀하시다 > 말씀하세요 = 말씀하셔요 The past form of "말씀하시다" is "말씀하셨다" "말씀하세요" is preferred in the present tense, and often used in everyday Korean. \^o^/

어미 '(으)셔요(시-어요)'와 '(으)세요'는 둘 다 표준어입니다. 원래, 어미 '(으)세요'는 서울 사투리였지만, 1980년대 중반부터 표준어(standard language)로 인정되었습니다. 음...수진님은 서울·경기를 제외한 지방사람들을 죄다 북한사람으로 만드셨네요.ㅎ