Why does this change the BackgroundColor3 to 50980?

Can anyone tell me why this changes the BackgroundColor3 to 50980,50980,50980 instead of going from 200 to 199, 198 and so on?

for _,v in pairs(script.Parent:GetChildren()) do
    if v:IsA("TextBox") or v:IsA("TextButton") then
        v.MouseEnter:connect(function()
            for i = 1,20 do
                wait(0.1)
                v.BackgroundColor3 = Color3.new(200-i/255,200-i/255,200-i/255)
            end
        end)
    end
end

I know I can use v.BackgroundColor3 = Color3.new(180/255,180/255,180/255) or for TextButton's use AutoButtonColor, but I don't wanna do it that way.

Any help appreciated.