The revised MIG and OCF-18 reflect the recent change made to the SABS in which a pre-existing condition must have been documented by a health practitioner prior to the accident. The change is reflected in Section 4 of the MIG which deals with impairments that do not fall under the guideline. As for the OCF-18, changes have been made to the introductory Note box on page 1 and to the second question in Part 4.
http://williehandler.blogspot.ca/2014/01/fsco-has-released-revised-mig-and-ocf-18.html