Hi Orlando,
You can store the OFC register values as you have stated, but the offset can change with temperature. Let's say you calibrate the ADS1248 at room temperature, but the device will actually be running at a temperature different than the offset calibration temperature. This will affect the result. Offset is very easy to calibrate out. All it takes is the SELFOCAL command, unless there is something in the input stage that also affects the offset and the calibration is done with SYSOCAL.
In normal operating conditions, I just issue the SELFOCAL command shortly after power-up. But you can certainly calibrate and store the register values, and then restore the values again after power-up or reset.
Best regards,
Bob B