Morrison Supply sells pressured air devices that assist patients with breathing disorders during sleep. Theme devices are delivered to patients immediately upon completion of a diagnostics exam, and are subsequenty billed to insurance companies. Insurance companies sometime refuse to pay and/or only agree to a reduced price. Patients are then responsible for any amount denied by the insurance company, bic are often unable or unwilling to pay. Because clinical standards of cleanliness must be maintained, Morr is is unable to ac: cept returns for resale to others. Morrison is reluctant to litigate to collect unpaid amounts. As a result, Morrison experies in high rate of uncollectible accounts, and prepares a monthly adjusting entry for uncollectibles that is equiri 20% of sales, Morrison's Monthly sales and write-offs for the first quarter of 207 follow: (a) Prepare monthly journal entries to summarize sales on account, the recording of the provision for uncollectibles, and the actual write-offs. (b) The provision for uncollectibles is established at 20% of sales. Why are the monthly write-offs not also proportional to that month's sales? Does the amount written off in a particular month impact net income for that month