need help please i have and idea bit want to make sure im correct

Scenario D - Unearned Services Revenue. The company charges $100 per month to spray a house for insects. A customer paid $600 on November 1 in advance for six treatments, which was recorded with a debit to Cash and a credit to Unearned Services Revenue. At year-end, the company has applied two treatments for the customer. Step 1: Determine what the current account balance equals (before adjustment). Step 2: The current account balance should equal $400 as of December 31 (two months at $100 per month). Step 3: Record the adjusting journal entry to get from step 1 to step 2