The interim
calculation is a part of the cost calculations that a manager must do during
the work life of a machine or working system.
The task of
the interim calculation is to check whether the preliminary estimations of the
system costs were realistic and can be approved by the real work of the system.
If there are deviations, it is necessary to calculate newly and to correct the
data for the further use of the system. In extreme situations it can be optimal
to finish the utilization of the system earlier than planned and to sell it if possible,
in order to limit the economic damage.
This seems
to be simple, but it is not:
In contrast
to the pre-calculation, where the costs are calculated as average over the
total planned life span, now the real cost curves are observed. The experiences
with the curves of repair and maintenance costs of written-off machines show that they vary
extremely due to the age of the machine. So, in order to find a realistic view
from the machine, the real costs must be compared with the an estimation how
the cost curves normally will behave.