It is first critical to understand that, without first meeting you and examining you in person, it is completely impossible for me to be able to advise you responsibly and ethically- there is no surgeon anywhere who could answer your question without the benefit of an exam, and you should be very wary of one who says he can...
On the other hand, I would like to be helpful to you- so let me give you some general information I think you may benefit from.
Most male patients who have had a tummy tuck and chest reduction do so because at some point in their lives they were significantly heavier and they have since lost a lot of weight. This weight loss is commendable, and in point of fact, you DO have an overall excellent result from your first procedure. But it's important to understand that with weight gain and loss cycles, it is not only a problem of skin quantity that develops, but also one of significant loss of skin quality- and I would be that this lost skin quality is the reason you haven't been able to achieve the tight six pack appearance you want (again, I would have to examine you to be able to say with confidence). Once skin has lost these qualities, it is not possible to get it back (although there are some procedures that camouflage the problem).
So if you were my neighbor, friend, or brother, what I would tell you (provided your examination indicated what I believe it would) is that you are killing yourself to achieve something your body just isn't likely to do anymore- so don't. Enjoy the excellent outcome you have.