The withdrawal fee is based on the current median market price of the token at that time. This fee changes with the value of the token. A week ago, TRON TRX was only 10 TRX withdrawal fee, as the token was valued against the USD at a higher rate at that time. As TRX grows in value, the # of tokens charged at withdraw will reduce, but in the end the value is still the same. 100 tron tokens today could be worth 10 tokens. More about Tron price prediction.