Sometimes you will sell your client a certain number of hours without really defining which services will be included in the work. However, you still want your people to start tracking time somewhere. In Productive, we call this Open hours.
Open hours will appear in your budget only if you have created a project from scratch, without defining financials/services in advance in your sales deal.
Open hours exist so that your people can start tracking time on a project before you've defined specific services.
Later, when you edit the budget and assign services, you can move the tracked time from Open hours to those services.