Changing Probationary Evaluation From and To Date automatically based on Hire Date

We are having probationary evaluation for new hires. Probation document is configured as a standard document and will automatically get created on New Hire's 60th day with the firm.
Probation Evaluation Review Period is set as a single long review period - i.e Review Period will be from 1.1.2020 to 12.31.2050.
Probation document is automatically created via scheduled process.
When document is automatically getting created, system takes the Review Period Start date and end date as start and end date of new hire's probation document. In this case new hire's document will be created for the period of 1.1.2020 till 12.31.2050, which does not represent actual probation period.