Why is the datastore save flipping values?

The time I first went on, I had 50 iron, and 2 gold. The next time, now I have 50 iron and 2 tin. The gold somewhat changed to tin, and I can't find the problem whatsoever.

This is what i'm talking about here Look at this: LINK The location of those is at ReplicatedStorage, if it helps.

SCRIPT BELOW

local DSService = game:GetService('DataStoreService'):GetDataStore('stpre')
local Items = game.ReplicatedStorage.CONFIG.Materials:GetChildren()
game.Players.PlayerAdded:connect(function(plr)
	
	local key = 'id'..plr.userId
	
	local savedvalues = DSService:GetAsync(key)
	
	local main = Instance.new('Model', plr)
	main.Name = 'inventory'
	local inv = Instance.new('Model', main)
	inv.Name = 'materials'
	local wepinv = Instance.new('Model', main)
	wepinv.Name = 'weapons'
	local utils = Instance.new('Model', main)
	utils.Name = 'utilities'
	
	for _,v in pairs(Items) do
		local ins = Instance.new('IntValue', inv)
		ins.Name = v.ItemName.Value
	end	
	
	if savedvalues then
		for _,v in pairs(Items) do
			for _,vv in pairs(inv:GetChildren()) do
				if vv.Name == v.ItemName.Value then
					vv.Value = savedvalues[v.ID.Value]
				end
			end
		end
	else
		local vts = {}
		for _, v in pairs(Items) do
			for _, vv in pairs(inv:GetChildren()) do
				if vv.Name == v.ItemName.Value then
					table.insert(vts,vv.Value)
				end
			end
		end
		DSService:SetAsync(key, vts)
	end
end)

game.Players.PlayerRemoving:connect(function(plr)
	local key = 'id'..plr.userId
	local items = plr.inventory.materials
	local vts = {}
	for _, v in pairs(Items) do
		for _, vv in pairs(items:GetChildren()) do
			if vv.Name == v.ItemName.Value then
				table.insert(vts,vv.Value)
			end
		end
	end
	DSService:SetAsync(key, vts)
end)