I believe with careful & confident preparation before and during exam, you should be able to boost your 5.5s to at least 6. CEC will be integrated into EE starting this January, and there are many unknowns associated to that. Most of the seniors here would have advised you to take CEC as soon as possible.
Your english score is one of the basic requirement to be considered in CEC. If you don't meet that bar, your application will be returned immediately, regardless of any reasons/excuses you provide them. These Visa Officers are just following their protocols...
