There is a significant amount of discussion on what should constitute halogen-free. Most camps have leaned toward the 900 ppm of Br and 900 ppm of Cl which already exists in the IPC PCB halogen-free specification. Other camps suggest that it should just align with the RoHS restrictions of 1000 ppm of each.
From a technical perspective, there probably isn't much of a difference between the 900 ppm and 1000 ppm. It seems to me that 1000 ppm would be cleaner, but I don't have a strong opinion either way. We will soon see where the maximum level of allowed halogens falls.