Modal logic is used in a similar manner to the conception of Flatland. It is amusing to think about how imaginary two dimensional creatures would interact in a two dimensional world--especially when we consider what it would be like when we interacted with them.
This is meant to give us some sort of analogy of higher dimensions may interact with our usual 3 dimensional conception of the spatial world. However, nobody would make statements about Flatland that are false in three dimensions, and claim that it is true about our world.
But this did trigger a thought about a perhaps "higher dimensional conception" where both statements where true.
For instance, if we assume that there is only one entity, say Atman, and that we are all just Atman interacting with Atman. Suppose all existence is Atman, and Atman thinks. In this case, both "I think therefore I am" and "I am therefore I think" are valid. In this case, it is Atman, that is speaking.
Perhaps, you, @FireShield, and @Ginko are simply Atman expressing thoughts directly
EDIT: All Descartes needed was "I think therefore I am". The reverse did not need to be considered. If he was doubting things, he was open to both the possibility of other things existing and not existing. "I am therefore I think" needs more certainty about other things. (Again, "I am and I think" is fine)