First, it is not a good idea to store calculated data in a table. The correct place for doing math functions is in a query. The reason is simple. If you keep the calculated data in a table, you have to re-do the math to update each of the calculated fields every time you make a change.
The correct method would be to create a query that displays the calculated stats, then use that query for your forms or reports.
You don't have to re-do the maths each time, it's already done when you open the query. The only updating required is for the fields in your table that hold the base data your stats are based on.