Why doesn't this value-change... change?

I'm trying to make the variable kills so that it only counts from the start of your KOs and not from 0.

kills = 0
game.Players.LocalPlayer.CharacterAdded:connect(function()
	kills = 0
	local start = game.Players.LocalPlayer.leaderstats.KOs.Value
	game.Players.LocalPlayer.leaderstats.KOs.Changed:connect(function(amount)
		kills = amount - start
	end)
end)

Example, if I had 0 kills, and get 5 kills, it will be 5 kills, ok. But in my next character respawn, (now I still have 5 kills in my leaderboard), if I get 5 more kills (10 in total), it will not say 5, it will say 10. How do I fix it so it says 5 only? And the thing saying it is the variable kills.

kills = 0
game.Players.LocalPlayer.CharacterAdded:connect(function()
    kills = 0
    local start = game.Players.LocalPlayer.leaderstats.KOs --You can't use .Value in a variable
    game.Players.LocalPlayer.leaderstats.KOs.Changed:connect(function(amount)
        kills = amount - start.Value
    end)
end)

I don't know why, but this just happens, you can't use '.Value' when setting a variable