Over$-$ or Under$-$applied Overhead: Explain the concept of over$-$ or under$-$applied overhead. What are the potential causes of this situation? How can companies adjust for over$-$ or under$-$applied overhead at the end of an accounting period? What are the implications of choosing different adjustment methods $($e$.$g$.,$ write$-$off to cost of goods sold, proration among accounts$)?$ Expand upon your answers.