Hi Natasha, 2.3.3 is out. Unlike the beta you are using, there are two filters you can hook to:
wjecf_bogo_product_amount_for_coupon( $quantity, $coupon )
wjecf_free_product_amount_for_coupon( $quantity, $coupon )
So if you’re using the script for BOGO, make sure you hook to the wjecf_bogo_product_amount_for_coupon instead of wjecf_free_product_amount_for_coupon.