Contacts/glasses prescription question, regarding astigmatism?

When discussing contact lenses everything starts at the glasses Rx. Your Rx says that your right eye or OD has a sphere power of -0.25, meaning that when looking at your eyeball or cornea as a 360 circle, all degrees require -0.25 diopter correction. However at axis or degree 83 you require an additional -2.50 correction meaning that at that axis your correction is actually -2.75. The same concept applies to your left eye or OS. So astigmatism means that there exists an oval shape at a particular axis in the eye ball or cornea. The Biofinity prescription is perfect. Companies do not manufacture all lenses in one degree corrections. So the closest to 83 is 80 which is the right option to take - always towards a principle axis. BC is base curve or the back side curve of the contact lens which is the surface that sits on the cornea once your lenses are inserted in your eye. So all-in-all you were fitted according to the recommended methods.