Why can't my Seller pay any portion of the escrow fee?

When a Broker transaction is set up confidential or transparent to Buyer, the Seller cannot pay any portion of the escrow fee. This keeps the Seller from knowing the Brokers commission and the purchase price. The Broker can have the Seller pay the entire escrow fee or half of the fee if the transaction is set up as Transparent to Buyer and Seller or Transparent to Seller.