Is there a way to add to a LUA script for correction of temp?

need to add about 20degrees onto a temp sensor due to inability to locate it exactly where i want too (place i put it reads apx 20degrees lower)?

excerpt from script here:--

local jeemon={
      port="/dev/ttyUSB0",
      baud=57600,
      stop=1,
      databits=8,
      parity="none",
      flow="none"
}

-- Keyed by NODE ID
local nodes = {
   [2] = RoomNode{base="dbzoo.livebox.jeenode:pond", endpoints={light=1,temp=1,lobat=1}, ttl=1800},
}

function init()
   monitor(jeemon, nodes)
end