Weak arguments, the result below is not a contradictiion. To state something 'could' swap good and sin does not contradict the statement 'must want there to be as little suffering' etc.
First of all, you could does not necessarily mean would. Could merely accepts that if there was a a god being it would have the ability but not necesarily use it. Secondly who says all sins cause suffering

This test is weak.
You're under fire!
You claimed earlier that any being which it is right to call God must want there to be as little suffering in the world as possible. But you say that God could make it so that everything now considered sinful becomes morally acceptable and everything that is now considered morally good becomes sinful. What this means is that God could make the reduction of suffering a sin... yet you've said that God must want to reduce suffering. There is a way out of this, but it means biting a bullet. So you've got to make a choice:
Bite the bullet and say that it is possible that God wants what is sinful (to reiterate the argument here - she must want to reduce suffering; she could make the reduction of suffering a sin; but if she did so, what she wanted (reducing suffering) would be sinful).
Take a direct hit and say that this is an area where your beliefs are just in contradiction.