I beleive:
(1) Physical presence of 30 months needed ONLY between Green Card Date and date of application.
(2) Continuous residence needed at all times (even upto the day of the citizenship interview).
As per the law (INA Act 316) - note the contents of (1) and (2)
No person, except as otherwise provided in this title, shall be naturalized, unless such applicant, (1) immediately preceding the date of filing his application for naturalization has resided continuously, after being lawfully admitted for permanent residence, within the United States for at least five years and during the five years immediately preceding the date of filing his application has been physically present therein for periods totaling at least half of that time, and who has resided within the State or within the district of the Service in the United States in which the applicant filed the application for at least three months, (2) has resided continuously within the United States from the date of the application up to the time of admission to citizenship, (3) during all the periods referred to in this subsection has been and still is a person of good moral character, attached to the principles of the Constitution of the United States, and well disposed to the good order and happiness of the United States.
I am banking on this - I have finished my Physical presence and plan to be on a project abroad for the next 1 year. In the interim, plan to visit as needed to maintain the "not out of US for more than 6 months" rule.
My GC date is Dec 25, 2000. Plan to file in 1st week of October 2005. During the time out of US, will continue to maintain apartment etc. in the US and will be paid in the US from my own company. Do you see any problems with this, JoeF, Rahul etc? Thanks for all your help.