Service Contract entry P1720/P1721

Hello

We are using the service contract entry applicaiton P1721 and advanced pricing to pull through the unit price.

Can someone please confirm should the billable duration field be manually populated with the months or should this be automatically calculated. 

We will be haivng some contracts that are partial years hence the question about th ebillable duration field as we currenlty price by months not days and if you take a month like febm, the price is different calculate over days versus month price.

Eg Contract for year is $1185.00

Partilaayear ito be 01/02/14 - 31/03/14 - 59 days

For monthly price $1185.00/12 * 2 = $197.50

For daily price $1185.00/365 * 59 = $191.55