Digiville, Inc. is a calendar year, accrual basis taxpayer. It sells multiple brands of computers, smart phones, digital cameras and camcorders, and other digital products. Its marketing strategy is based on providing substantial, extensively advertised rebates on products otherwise sold at list price. Although Digiville fully expects that many purchasers will never get around to claiming rebates and that others will file claims that fail to follow its clear, but detailed filing rules, the rebates are large enough to motivate most of its customers to file claims. Most of Digiville's sales take place in the second half of the year. Digiville would like to deduct on its federal income tax return rebates attributable to sales during the year that Digiville will not actually pay until the following year. Assuming it can do this, can it deduct rebates attributable to all sales during the year for which rebates are expected to. be claimed (based on a reasonable estimate), rebates attributable to sales during the year for which rebate claims have been filed but for which qualification has not been determined as of the end of the year (again based on a reasonable estimate); or only for rebates attributable to sales during the year as to which claims have been filed that have been determined to be qualified as of the end of the year. Regardless of the rebate claims for which deductions can be taken, can Digiville delay payment until the following fall in order to pay one year's rebates with proceeds from the following year's sales? If not, when must the rebates be paid to be deductible in the year in which the qualifying sales were made? Explain with references to primary sources.