Loading Screen Activate Sooner?

Once using the loading screen, why does it show the default loading screen before using the custom loading screen that's supposed to override the default? It shows the default for about 5 seconds (or more), and then it removes. Is there a way to speed up the process?

I got this script from the ROBLOX wiki:

local PlayerGui = game.Players.LocalPlayer:WaitForChild("PlayerGui")
PlayerGui:SetTopbarTransparency(0)

local screen = Instance.new("ScreenGui")
screen.Parent = PlayerGui

local textLabel = Instance.new("TextLabel")
textLabel.Parent = screen
textLabel.Text = "Loading"
textLabel.Size = UDim2.new(1,0,1,0)
textLabel.FontSize = Enum.FontSize.Size14

script.Parent:RemoveDefaultLoadingScreen()

local count = 0
local start = tick()
while tick() - start < 6 do
    textLabel.Text = "Loading " .. string.rep(".",count)
    count = (count + 1) % 4
    wait(.3) 
end

screen.Parent = nil