80Step 10—weighted average percentage difference for listed brand and all related brands

#### 80 Step 10—weighted average percentage difference for listed brand and all related brands (1) Work out the weighted average percentage difference for the listed brand and all related brands. (2) The weighted average percentage difference is the amount (expressed as a percentage to 2 decimal places) worked out as follows: (a) for each pharmaceutical item with the same drug and manner of administration as the listed brand (including the pharmaceutical item of the listed brand): (i) multiply the total adjusted volume for the brands of the pharmaceutical item (see step 7) by the average approved ex‑manufacturer price for a brand of the pharmaceutical item (see step 3); and (ii) multiply that amount by the weighted average percentage difference of the brands of the pharmaceutical item (see step 8); (b) add up the amounts worked out under subparagraph (a)(ii); (c) add up the amounts worked out under subparagraph (a)(i); (d) divide the amount worked out under paragraph (b) by the amount worked out under paragraph (c). (3) However: (a) if the amount worked out under paragraph (2)(c) is zero or less, the weighted average percentage difference is zero; and (b) if the amount worked out under paragraph (2)(d) is 99% or more, the weighted average percentage difference is 99%.