Rumsfeld has said that much of Chalabi's intel was considered highly helpful by the ground commanders during this pacification/reconstruction period.
I agree with your take, the termination of the "consulting" agreement is probably timed to cause as little interference and internal trouble as possible with the 6/30 handoff looming.
Thank you. He has provided invaluable information and assistance and has been rewarded with non-stop smears by DoS bastards to their toadies in the press.