Eligible Costs. A taxpayer may only claim the credit for allowed costs incurred during its taxable year. If the taxpayer has a short taxable year, only the allowed costs incurred during the short taxable year are allowed on the short year return. If the taxpayer incurs allowed costs in 2 taxable years during a calendar year, one of which is a short taxable year, the taxpayer may only claim a credit on the short taxable year return in an amount equal to the total credits certified by the Department multiplied by a fraction: The numerator of which is the allowed qualified capital costs incurred during the short taxable year; and The denominator of which is the allowed qualified capital costs incurred during the entire calendar year.