Chang Co. sold a copier costing $7,500 with a two-year parts warranty to a customer on August 16, 2011, for $15,000 cash. Chang uses the perpetual inventory system. On November 22, 2012, the copier requires on-site repairs that are completed the same day. The repairs cost $99 for materials taken from the Repair Parts Inventory. These are the only repairs required in 2012 for this copier. Based on experience, Chang expects to incur warranty costs equal to 4% of dollar sales. It records warranty expense with an adjusting entry at the end of each year.