AD8417 Ratiometric Accuracy of referance

I can see Ratiometric Accuracy =0.5-0.2% to 0.5+0.2% (0.499 to 0.501) at table 2 on AD8417 data sheet page 3.

And, I can see that accuracy of approximately is 0.5% at "SPLITTING AN EXTERNAL REFERENCE"  page 12  on AD8417 data sheet.

How do I need to understand  these differences (between 0.2% and 0.5%) for ratiometric accuracy of internal reference.

Best  regards

noza