whether rentry permit is valid after one enters usa and departs immediately

[dramit]

My father who is a greencard holder came to usa on august 2002.And before going back to india had applied for a 2 year reentry permit.As we didnot receive any answer from INS due to long processing time,he came back to usa in 2003 august to be in safe side(before 1 year) And then again went back to india.But this time he didnot apply for reentry permit as decision on first reentry permit was still pending. We got a reentry permit for him in march 2004 which was issued on march 2004 and is valid upto march 2006.
But someone told me that as my father once came to usa within one year, after originally applying for a reentry permit for two years , that permit which is currntly valid upto march 2006 is no longer of any use and is invalid now.So my father has to come back before august 2004(within one year of his last departure from usa in august 2003) to avoid being cancelled his green card.
I also heard that my father should have applied again for rentry permit during his last visit in 2003 if he intends to remain outside for more than one year. My father is currently planning to come not before february 2006.
Is this true?If yes, why do they give rentry like a passport book so we can enter multiple times during validity of rentry permit and immigration officer can stamp in reentry permit everytime we enter usa. Also this means that BCIS is making double money by not issuing reentry permits within one year so we have to apply for rentry permit again and pay them fees again.
Please reply who has knowledge in this matter, especialyy like experience forum members like ****.

[dramit]

Thank you **** for your reply.