You should have asked the Physician why.
Each portion of that category is given for a reason. Here is the criteria for his decision:
O3 - assigned to the member who has some specific employment limitation(s) which can be clearly and specifically detailed, and which prevent the member from fully meeting the Generic or the MOC task statements.
G3 - assigned to the member:
a. who is considered likely fit for field exercises, sea environment, isolated postings and operational taskings for periods up to six (6) months;
b. who has a known requirement for scheduled medical service (see definitions in Chapter 2, 4.c.) by an MO but no more frequently than every six (6) months;
c. whose limitations resulting from a known medical condition do not pose an unacceptable risk to the health and/or safety of the individual or fellow workers in the operational/work environment;
d. who may require and take prescription medications, the unexpected discontinuance (unavailability) of which will not create an unacceptable risk to the member's health and/or safety; and/or
e. who may require a medical evaluation before being sent on the tasking.
And that it is permanent, means the condition will not improve in 1-2 yrs.
This is for information only. More interesting reading can be found here:http://www.forces.gc.ca/health-sante/pd/CFP-PFC-154/default-eng.asp
I don't know, want to know, nor actually care about your case. But as someone who works in this field, I believe you should at least be armed with this information so you may go back and ask the right questions.