Hi Martin,
Do not take the netbacks numbers to seriously. They have no accounting meaning and as such do not represent company ability to pay the bills, debt or invest for the future.
The netbacks are depending on the average price of bitumen in recording period, operational expenses, transportation cost and Royalties. CLL Royalties will change in next couple of years.
As wisely pointed by Rebel netbacks do not include the interest expenses and additionally they do not include capital cost of maintaining the production ($37 million= $7/bbl) and G&A cost.
Hope this help with your calculations. Good luck, Jurek.