Font size of the nameplates

[Dasteman]

I'm using currently a script that I've found on another forum to make text font on the nameplate smaller.
It works but it's applying its effect multiple times after long session in the game.
Text gets so small that you can't read anymore.

Do you know what's wrong with that script?

local frame = CreateFrame("Frame")
    frame:SetScript("OnEvent", function()
    --big plates with small text
    DefaultCompactNamePlateFrameSetUpOptions.useLargeNameFont=false
    end)
    -- Register for interesting events
    frame:RegisterEvent("PLAYER_ENTERING_WORLD")