The author outlines expenses as about 16% of revenue but I wonder how much the production of the new course material cost? How long did it take to produce? What

The author outlines expenses as about 16% of revenue but I wonder how much the production of the new course material cost? How long did it take to produce? What does the author value their time at? What other previously incurred expenses are not accounted for (i.e. recording equipment or software).