Time Dependent tab in Asset Master Data

Hi people!

Please, could you help me:

We have created a new Asset Master Data and we defined a specific cost center in the table "Time Dependenet".

We don´t know the reason the system shows us in the table "Time-Dependent" a description:

Interval from 1900-jan-01 until 2015-may-31. Why 2015-may-31.

We waited until 9999-Dec-31  (Obs.: The cost center is valid until 999-Dec-31)

Could you tell us why the system put the data "until" 2015-may-31 instead of 999-dec-31?

Thanks,

RGN