i have this too and i think i understand why. Even though your computer is authorized for your apple ID, and your other devices are set up with your apple ID's, none ot them have iTunes "associated with" your apple ID's because you haven't activated iTunes Match nor have you done any "automatic download", nor have you re-downloaded a previsouly purchased (and previously downladed) item. Only of these "iTune in The Cloud" feature would trigger the association and the 90-day lock out.
It also seems that the "Transferring Purchase" from device to computer does NOT trigger the association neither. (it didnt on my computer).