Dosent Add Value Only Substracts?

Long Time No See So My Script Here Wont Add The Value When The Value Is Set To 2 It Would Only Add When It Is 1 When The Value Is 2 Is Makes It 1 Lol Why Doe Also If I Did A Stupid Mistake I Am Sorry I Am Really Tired Right Now

local db = false
script.Parent.Touched:Connect(function(Hit)
    if Hit.Parent:FindFirstChild("Humanoid") and not db then
        db = true
        local Player = game.Players:GetPlayerFromCharacter(Hit.Parent)
        local SD = Player.SD
        SD.Value = SD.Value + 1
        local PowerUpGUI = Player.PlayerGui:WaitForChild("PowerUp").Frame
        local TT = script.TextLabel:Clone()
        TT.Parent = PowerUpGUI
        script.Parent.CanTouch = true
        for i = 1, 5, 0.1 do
            TT.Text = i
            wait(0.1)
        end
        db = false
        TT:Destroy()
        SD.Value = SD.Value - 1
    end
end)