What kind of information can be assumed from sensor accuracy graph
Your main problem is that the graph is headed 'Typical'. There are no guarrantees associated with this graph.

The fact that the pressure output varies by more than 20mBar over temperature at zero pressure ought to alert you to the fact that there are things (like temperature) that will affect its accuracy. These will include excitation voltage, age, and mechanical errors like hysteresis, retrace and stiction.

This means the pressure sensor itself is simply not stable enough to be worth attempting to correct to better than 10 or a few tens of mBar, at least not for absolute pressure, and not over a long time. 

Establish what the stiction error (minimum change of pressure required to change the output, after a previous change in the same direction), hysteresis error (minimum change of pressure required to change the output after a previous change in the opposite direction), and retrace error (difference in output at a pressure of p0, after visiting a pressure of p1) before you decide whether it's worth the effort to try to calibrate out the remaining few tens of mBar error.