I replied earlier with my smart phone but the reply got mixed into what you wrote:
The problem really has to do with who the mtm supplier is or uses. Mtm can be a blessing or a curse because if what is expected gets delivered then great a blessing. If you screw it up...and its easy to screw up....then you don't get what u expect and its worse than rtw. Maybe I should write an article on how to select a good mtm supplier since there are so many.
Anyway, the shirt is too big on you. All of your posture elements that ideally dictate how the pattern should be cut may not have been taken into consideration completely which is where those odd wrinkles come into play. Shrinkage? Yes and no. Good tightly woven cotton will not shrink much. Maybe 3-5%? Also, did the darts come sewn in like that? There's no reason for darts on a mtm shirt and they don't even fix the fit. It looks like an oversized express shirt. It can be altered. I'd rip those darts out, take it in thru the sleeves and sides. When I dart those HUGE rtw shirts I dart them right next to the side seam so u can barely see them. Who wants to wear a woman's blouse?
Ultimately the problem is a breakdown somewhere between the mtm reseller agent and the maker. Probably on behalf of the seller. My guess of course...
Next time you go to an mtm supplier/agent, make sure they account for every element of your posture as possible. It can be so many things that ultimately affect the way the pattern is cut but if they're all accounted for as closely as possible along with accurate measurements then your garment may only be off SLIGHTLY at which point you identify the little areas that need to be fixed for the next round and evolve through the process. I believe jefferyd talked about this in his blog about how roughly only 5% of the population wearing tailored clothes has a near perfect fit and it's all because of proper ongoing collaboration/communication between client and cutter (seller in this case).
Lastly, if you really want your clothes to fit the best, do some homework on your own to determine what type of posture you've got in every area of your body. Have someone take pics of you wearing a tighter tshirt and boxers in front back side relaxed poses. Study your body. What do you see? Take it to a GOOD tailor and ask him/her what is going on. If you know your posture and you go to an mtm supplier and they don't account for something, then you know they're either untrained, careless, or in a hurry for that commission check. An informed client has a better shot at preventing this than an uninformed client.