RE:WCS VS WTI...WCS is the real number they should be using. When they make an announcement, they use a fixed differential in the fine print.
Dec 9th announcement @70 WTI. CF=225, FCF=105, WCS delta 13.00 FX.78, AECO 3.50
Currrently WCS delta is 14.00, FX is .7877 and AECO is 3.79. SInce both WCS delta and FX are worse, they would be a bit short of guidance.