Tax relief

The lease will be over 5 years with lease payments of $146,000 annually (at the start of each accounting period). Tax is payable 1 year after the accounting year-end and the corporation tax rate is 25%. Maintenance is payable by the lessor and costs $20,000 per annum payable at the end of each year, including the last year in preparation for sale. The residual value is expected to be $40,000 (the expected tax written down value at the end of the lease) and the lessor will retain that.

Answer:
Years 1-5 maintenance of $20,000 and years 2-6 tax savings on the maintenance costs discounted at 6% discount rate.

Annuity factor 5 years at 6% = 4.212
$(20,000) x 4.212 = $(84,240)
$20,000 x 25% x (4.917 – 0.943) = $19,870

Net PV = $(64,370)

My question:
Where does they say that the has any tax saving on the maintenance, I really am confuse