Generally speaking, when modifications that increase airflow have been done, and the ECU has NOT been tuned to suit, the car will be more sensitive to the BOV adjustment. A bone-stock car, or one that has been modified AND tuned will usually be less sensitive, often allowing up to 100% atmosphere venting without issue.
This is because increasing the airflow (via increased boost, free-flowing exhaust or intake etc) without tuning the ECU to suit will usually result in rich mixtures. When an atmosphere-venting BOV is installed with such a combination, you’ll often find it’s harder to get the spring pre-load right, or that you need to run less atmosphere venting bias.
Note that is it NOT necessary to tune an ECU to suit a BOV, what you can see from the above is that if the ECU is already tuned correctly to suit the other modifications on the car, it is going to be less sensitive to the BOV settings.