Target utilization is a filed in station settings. It doesn’t mean something right now but in the future it will be used from auto-scheduler in order to know how many observation can schedule on a station. There are various variables around the concept that haven’t already defined and are still under discussion.
From station page you can schedule up to 1 day in the future, in the observations/new page up to two days in the future.
For an observation you need to know the orbit of the satellite. It is needed for calculating observation’s start and end time and the pair of elevation and azimuth for each moment. For calculations we use TLE (two line elements), which is a prediction set of orbital elements that are valid(accurate) for a period before and after a point of time.
TLEs for the satellites we have in db and use in network are updated from time to time. Allowing scheduling in far future will reduce the accuracy of the pass. In most cases, in which the satellites do not have an active way to change their orbit, 1-2 weeks old elements could be still accurate. However in satellites, like ISS or NOAAs, when they correct their orbit TLEs could be invalid after one or two days.
There is the auto-scheduler project, still under development but fully working. You can read more on auto-scheduling on this and this thread.