This metric takes into account all costs incurred by a business for a customer in a cohort. It differs from CAC in that it takes into account not only the cost of attracting, but also the cost of retention in the cohort.
To calculate this metric, simply add up all the costs of all scaling units during the life of the cohort, for this I recommend using the fixation of all touches of a scaling unit with the product, indicating the channel from which the scaling unit came, as well as the cost of this transition and then divide them by the number of customers in the cohort.