For roller bearings edge stresses can occur on high loading leading to different results than usually found in bearing catalogues. Therefor a second option exists for the calculation of effective static load capacity C0w.
If this option is selected the stress in the center of the roller is compared with the permissible stress as above. So edge stresses are not taken into account.
For ball bearings, this option does not affect the results, it only makes a difference for roller bearings.