As I know there is no possibility to add a new entry there through the application.

Technically it comes from the enumeration types defined in LOST_WON_API.
It only defined  Lost, Won, and NoDecision as options.
if you consider to change it by adding new options, you need to go for a customization.
Hope this info helps.
 

@Kelum Pradeep Kumara  Thanks for your answer.

I thought that ‘No Decision’ was added thru a basic data window and not in the standard IFS .