https://imgur.com/a/h4vkA
I used this script here
Code:
local r = reaper
local tr = r.GetSelectedTrack(0,0)
local _, chunk = r.GetTrackStateChunk(tr, '', 0)
r.ClearConsole()
r.ShowConsoleMsg(chunk:match'(VOLPAN.-)\n')
Another example
https://imgur.com/a/pDuyX
If you set pan in "Routing for track" window then it's ok