how to create a declining balance formula ?

Dear Sirs/Misers

How to create a depreciation formula which is based on days?

My company use the following formula :

Asset cost = 147,000

Depr Perc  = 25%

Life months = 48 (4 years)

Asst Acquired date            = Feb 20th , 2013

Start Depreciation date       = next month  (March 01st, 2013

It is calculate as follows :

1. Asset Cost * Depr Percentage : 147,000 * 25% =  36,750
2. Take the result (36,750) / number of days per year (365) : 36750 / 365 = 100.68 per day
3. Multiply the deprecation per day (100.68) by number of days per each month : March 2013 : 100.68 * 31 = 3,121.23 / April 2013 : 100.68 * 30 =3,020.55
4. As of dec 31st 013 it will result , the accumulated depr will be 30,809.59 as number of days are 306 days

As 01/012014 the net book value should be 116,190.41 (147,000 - 30,809.59)

January 2014 the result should be like this