What is the difference between load testing and discharging a LiPo?
You cannot test for "max discharge rate" using any of these methods, unless you have hundreds of cells you can afford to ruin. The max discharge rate is a parameter that was determined by cell manufacturer based on specified reliability and number of charge-discharge cycles. It can be determined only by mass testing and statistical processing/analysis. Typical discharge method is to use a certified "electronic" load with constant current settings, all after manufacturer's specified charging process.