I have successfully redeemed the coupon as the chips have been refilled. Unfortunately, the merge option wasn't available which left me with a bunch of smaller chip values. In regards to what to follow as example, looking at how bitmixer used to do everything was how people were liking it. Instead of a flat fee, allow people to manually set a fee ranging from 0.5-2%. If you let people to adjust their fees in the way of 0.8356%, 1.0346%, etc, people will never end up with the same fee.