Hey @slooowlearner, you're entirely right that the videos and lessons are out of sync. Based on early feedback to this unit we made some changes to the concepts that are introduced in those lessons which led to the inconsistency. It's an error we intend to fix on our next pass through that unit, but right now most of our curriculum attention is on doing a clean-up of Units 4-6. I hope it hasn't created to much disruption. We know a lot of students benefit from the videos and we didn't want to get rid of them based on a couple inconsistencies.
Hope that helps explain things but let us know if we can help more!