Increasing implant size to 640 cc? (Photo)

I had saline implants about 6years ago. I was about a size 36B in a bra before implants. I am 5 foot and weigh about 170 lbs. I had 540 cc, each side ,high profile implants. The surgeon done an Awesome job. I am wanting to goup 100 cc bigger. The surgeon thinks this will make me look chubby, as implants are more width than length. I am wanting my Breasts more bigger than how they have settled. Is adding te 100 cc going to be too Big ? I feel my Breast dont look as big with clothes on.6