Master Grill Company sells outdoor grilling products, providing gas and charcoal grills, accessories, and installation services for custom patio grilling stations.

Master Grill offers contract named MG100 to customers. Each MG100 contract comprises a free-standing gas grill for small patio use plus installation to a customers gas line for a total price $950. On a standalone basis, the grill sells for $800 (cost $470), and Master Grill estimates that the fair value of the installation service (based on cost-plus estimation) is $200. Master Grill signed fifteen MG100 contracts on May 30, 2018, and customers paid the contract price in cash on the signing date. The grills were delivered and installed on June 15, 2018.

Prepare journal entries for Master Grill for MG100 on May 30 and June 15, 2018. Show the supporting calculations.