Timesheet stop calculation


could you guys tell me were i can disable the calculation logic of the Timesheet? We have the problem that as a consulting company it is not so important to have every day booked with the right hours we just more write 01.01.23 - 31.01.23 70 Hours Worked.

But if we do this in ERPNEXT the System changes the Dates wich will reflect on the invoice.