Depreciation - different results on HP30b and on paper

[FabioBrasil]

Hello.
I come again to kindly ask for help from you who know a lot about HP. I cannot make the result of the calculation of decreasing depreciation (DecBal) provide the same result on the HP30b calculator and on paper.

The problem consists of the following:
- Cost (Czero)= $ 25000
- Salvage = $ 5000
- Life = 15 years
- Factor =10.174%

On paper D (n) = Czero * (1- Factor) ^ n
in year 1 I have 22,456.50
in year 3 I have 18,119.49
in year 6 I have 13,132.64
in year 12 I have 6,898.65
(n = year use as Factor 10.174%)

On the HP30b calculator (use as Factor 10.174%):
in year 1 I have 24,830.70 (R.Book)
in year 3 I have 24,494.94
in year 6 I have 24,000.08
in year 12 I have 23,040.16
Where am I going wrong? I couldn't get the answer on the Learning Modules.

Thanks!