[Sharlikran]

What I basically use now

function MasterMerchant:Initialize()
  local systemDefault = {
    <<stuff>>
  }
  self.systemSavedVariables = ZO_SavedVars:NewAccountWide('ShopkeeperSavedVars', 1, nil, systemDefault, nil, 'MasterMerchant')
  <<stuff>>
end

The last part is what the previous author put so I can't remove it. It would work the same as.

function MasterMerchant:Initialize()
  local systemDefault = {
    <<stuff>>
  }
  self.systemSavedVariables = ZO_SavedVars:NewAccountWide('ShopkeeperSavedVars', 1, nil, systemDefault)
  <<stuff>>
end

What is odd about what you are sharing, I don't have any issues adding a new value to the systemDefault table. In fact I loop over the table used by the saved vars to remove the old unused values.