Lean causes you to reduce your batch sizes. Rather than telling the customer we’re working on lesson 2, tell them we’re working on courseware increment #2, during iteration #2. Provide a scope commitment to them for that iteration, so they know that this courseware increment includes learning objectives (LO) 3.1, 3.2, and 4.1 through 4.5.
During the iteration, focus the work on a single LO at a time. Storyboard the one LO rather than the entire lesson. Then get the interactivity done for it and the media created for it. Perform the QA content checks for that LO. Define 'done' for the LO as ready to send to the LMS or learners. Now ideally you don’t have to touch this LO again. In the real world, the SME or customer always says, "Can you also change this and that?" So, you will have some degree of changes (rework discovery rate). Estimate historical rework rates, for example 10-20 percent, depending on the customer stakeholders involved with review. Monitor rework and talk to the buyer/customer if it gets above your planned amount.
Smaller batches also mean less scope, so fewer people are trying to coordinate with you at the same time, which reduces interruptions, and therefore reduces the waste of context switching.
Smaller batch sizes also means more even flow through your development pipeline, that customers see and inspect increments every two weeks. This builds trust between the customer and your team. It also helps your team get earlier feedback before they are done with the entire lesson. It costs less to do work once than twice, so earlier feedback reduces risk and helps your bottom line.