You can set up how many points minimum to redeem, but we don’t have a function to limit maximum points to redeem. You can hit INSERT key in points field in the payment window to automatically calculate how many points are available to redeem. WooPOS has a function (switch 049) to convert points to Coupon once points reach minimum redeem points. It’s hard to do everything exactly same way, especially on WooCommerce because plugins are designed by different people in different ways.