Reserve for estimated returns question

Hopefully someone can help out. What does the “costs and expenses” and “deductions” part mean from below? Reserve for est returns and allowances: balance at beginning of year: $500 costs and expenses: $14,000 deductions: $14,200 balance at end of year: $300 also, is it normal in the above example where you will see a low beginning and ending balance, yet the costs and deductions are a much bigger amount?