Are the formulas deliberately wrong in lesson 11.3.4. If they are I don't think it is a helpful way to learn as it is too easy to get confused and then loose the actual purpose of the learning exercises - it would be better to just say now create a formula to bring in the same data for the different line item. If it is not deliberate could they be corrected for other learners (Cost of Sales, Bonus and Car Costs are the ones I've found so far) in the future.