Shamrock Windows manufactures and sells custom storm windows for three-season porches. Shamrock also provides installation service for the windows. The installation process does not involve changes in the windows, so this service can be performed by other vendors. Shamrock enters into the following contract on July 1, 2020, with a local homeowner. The customer purchases windows for a price of $2,370 and chooses Shamrock to do the installation. Shamrock charges the same price for the windows irrespective of whether it does the installation or not. The customer pays Shamrock $1,920 (which equals the standalone selling price of the windows, which have a cost of $1,120) upon delivery and the remaining balance upon installation of the windows. The windows are delivered on September 1, 2020, Shamrock completes installation on October 15, 2020, and the customer pays the balance due. Given uncertainty of finding skilled labor, Shamrock is unable to develop a reliable estimate for the standalone selling price of the installation. Prepare the journal entries for Shamrock in 2020. (Credit account titles are automatically indented when the amount is entered. Do not indent manually. If no entry is required, select "No entry" for the account titles and enter O for the amounts.) Date Account Titles and Explanation Debit Credit Sep. 1, 2020 Cash 1920 Accounts Receivable 450 Unearned Service Revenue Sales Revenue (To record sales) Cost of Goods Sold 1120 Inventory 112 (To record cost of goods sold) Oct. 15, 2020 Cash 450 Unearned Service Revenue Service Revenue Accounts Receivable 45 (To record payment received)