My question is regarding when the the CMB was created. I understand that it is predicted to have been "when the universe cooled to about 3,000K". However, might it have been possible that different areas of the universe reached that temperature and decoupled a little earlier than others? This would mean there is some variation in the "Surface of Last Scattering" rather than being smooth. The idea is that this might describe the anisotropies of the relic radiation. The cooler areas would indicate places that cooled and decoupled further in the past (earlier in the universe's time-line) and that the hotter areas would indicate areas that cooled and decoupled a little later.