For this new semi-mount, you will add the order #30842 2.55ct oval lab diamond and order #25975 3.539ct(11.60x6.43x4.39mm)
It is $528 for this XR2051 ring semi mount without #30842+27404 center, with total 3 pieces round lab diamond accents in 10K yellow gold and and 10K white gold ring head. (2.8mm band width and 1.8mm band thickness. )
After returning the #25975 setting you will have $439.11 credit, the price difference that you need to pay for this replacement semi-mount is $88.89.