08 June 2011
AO for assessment u/s 147 (escape assessment) is the same person who is AO for assessment u/s 143 (regular assessment). Actually, after issuing notice u/s 148 assessment is done u/s 147 and 143. So there is no separate AO. Depending on the quantum of total income AO could be ITO or ACIT.
For your second query- YES, present AO can issue notice for assessment of earlier years. Division of jurisdiction is administrative matter done for ease of work only.