Under Georgia O.C.G.A. § 33-7-11, when an insured selects 'add-on' uninsured/underinsured motorist coverage rather than 'reduction' UM, the available UM benefit is calculated by:

Why this is the answer

Under O.C.G.A. § 33-7-11(b)(1)(D)(ii), add-on UM treats the at-fault vehicle as uninsured to the full extent of the insured's UM limits and pays in addition to the at-fault driver's available liability coverage, so the full UM limit sits on top of the liability payment (subject to the insured's total damages). Reduced UM, by contrast, covers only the difference between the at-fault driver's available liability coverage and the UM limits. Add-on applies unless the insured rejects it and selects the reduced form in writing.