My impression was that the pre-change cancellation rate was based on all customers over the lifetime of the product (they did calculate the 61 day average from

My impression was that the pre-change cancellation rate was based on all customers over the lifetime of the product (they did calculate the 61 day average from this), whereas the post-change was only for the new customers in the last two months (the max it could be, and the only thing it makes sense to measure).