What are you trying to achieve, we need more details? What is the rate that you want to compute? At what level (dimension/partition) are you counting the ids? You could try and achieve this using an LOD ...
Your calculation is based on a position in the underlying table that supports the viz - using an excel analogy the calculation is saying starting at the current cell move up one cell and take that value to use as the denominator
you could use Previous value to accomplish the same thing but it to is a table calculation
Table calculations are the tool that tableau uses to move around a table - is there a reason you want to avoid the table calculation -