Alterations in a Belvest Jacket

[chapunso]

Dear Forum Fellows: I am in great distress after the purchse of a belvest jacket that originally was on the tight side. The "taylor", or alterations guy, I must say, at the store suggested to open the side seam to let one inch on each side. As a consequence of that, a horizontal wrinkle now can be seen just under the arms, and I see that the side vents are slightly too opened. I took it to my taylor who told me that he would do nothing because somebody else already altered the jacket, and you know what, I think he is a great taylor, but a bit of a divo or primadonna.
He suggested to open the sides again and the back of the arm holes; in doing that he can reshape the jacket, eliminating the excess cloth that now makes the wrinkle and put it under that arms seam. this will also make the side vent to fall perfectly vertically, but he might have to give some extra length to the central cloth between the two side seams, because when pulling up, it may have shortened.

HELP!!!!