http://uscis.gov/graphics/howdoi/address.htm#what
says...
You do not need to include temporary addresses as long as you maintain your present address as your permanent residence and continue to receive mail there.
Since I maintain my permanant address, I do not need to report the pemporary address.
What Should I Include?
For the Form AR-11: Complete the information requested on the form, including present address, last address (most recent only), alien or registration number, country of citizenship, date of birth, and your signature.
You do not need to include temporary addresses as long as you maintain your present address as your permanent residence and continue to receive mail there.
When sending us a change of address, you do not need to include numerous last addresses; only the most recent last address is needed.
Be sure to also indicate in the appropriate block on the AR-11 your current employment and school, where applicable.
Additional Information
The address reporting requirement should not be confused with renewal or replacement of lawful permanent resident cards (Form I-551) or replacement of other evidence of alien registration, such as the Form I-94, Arrival-Departure Record; I-186, Nonresident Mexican Border Crossing Card; I-688, Temporary Resident Card; or, I-766, Employment Authorization Document.
Penalties for Failure to Comply
A willful failure to give written notice to the USCIS of a change of address within 10 days of the change is a misdemeanor crime. If convicted, the alien (or parent or legal guardian of an alien under age 14 who is required to give notice) can be fined up to $200 or imprisoned up to 30 days, or both. The alien may also be subject to removal from the United States. (INA § 266(b)). Compliance with the requirement to notify the USCIS of any address changes is also a condition of an alien’s stay in the United States. Failure to comply could also jeopardize the alien’s ability to obtain a future visa or other immigration benefit.