What ?   Closing costs are added to the cost basis of the property when you place it into service.  Why are you trying to enter them now separately ?

I used the wrong term. I'm trying to amortize them and not depreciate.

Did you refinance the loan ?   Is that what you are calling closing costs ?  

yes

That is what I selected. I defined the life as 15 year but could not set the method to 150% DDB

The Default for amortization is deducted ratably over 15 years(180 months).. you cannot choose 150%DB ... the program will do this automatically ... review the depreciation worksheet.