On December 28, 2018, Tristar Communications sold 20 units of its new satellite uplink system to various customers for $10,000 each. The terms of each sale were 2/10, n/30. Tristar uses the gross method to account for sales discounts. In what year will income before tax be affected by discounts, assuming that all customers paid the net-of-discount amount on January 6, 2019? By how much?