I am looking for a good formula to use to find the leak rate for refigerant. I am currently using one from my company that is as follows:

leak rate% = pounds full charge / pounds gas added x 365 / # of days last added x 100

this seems to be way to complicated and your answers can vary way over 100% leaks rates. I am just curiuos to see some other variations out there that might make more sense.