The albedo correction depends on the angle between the normal to the Sun surface at the flare location and the viewing direction. The angle can be specified directly by supplying an angle (in degrees) or by specifying the position of the flare in arcsec.
If you set the source angle and xy position in the same call, the xy position takes precedence. If you set an angle directly, the parameter spex_source_xy will be set to [-9999.,-9999.] since it can not be computed from the angle.