service for the windows. The installation process does not involve changes in the windows, so this service can be performed by other vendors. Grouper enters into the following contract on July 1, 2020, with a local homeowner. The customer purchases windows for a price of $2,470 and chooses Grouper to do the installation. Grouper charges the same price for the windows irrespective of whether it does the installation or not. The customer pays Grouper $1,940 (which equals the standalone selling price of the windows, which have a cost of $1,050) upon dellvery and the remaining balance upon installation of the windows. The windows are delivered on September 1,2020, Grouper completes installation on October 15, 2020, and the customer pays the balance due. service for the windows. The installation process does not involve changes in the windows, so this service can be performed by other vendors. Grouper enters into the following contract on July 1, 2020, with a local homeowner. The customer purchases windows for a price of $2,470 and chooses Grouper to do the installation. Grouper charges the same price for the windows irrespective of whether it does the installation or not. The customer pays Grouper $1,940 (which equals the standalone selling price of the windows, which have a cost of $1,050) upon dellvery and the remaining balance upon installation of the windows. The windows are delivered on September 1,2020, Grouper completes installation on October 15, 2020, and the customer pays the balance due