Roommates. Renter's Rebate Claim.

I asked for the LC-142 form from my landlord. but he said to only claim 1/3 of the allocable rent and have my other two roommates do the same. I was wondering if that was possible or can Ijust claim the entire thing and split it between the three of us? I t also tells me to write down their names and ssn but one is rarely home and has been here for half a year. what do i do?