I can't get the script to check if all of the part's magnitude compared to another. Any help?

So, I have a building system, and I want to get it to not place in the same position of another. There are collision parts inside all of the models. This is the part I'm having a problem with. It is only doing it for the recent model added to the folder,

for a, b in pairs(placedTiles:GetChildren()) do
        print("Finding Touched")
        if b:FindFirstChild("Selection") and (b.Selection.Position - tile.Selection.Position).Magnitude < 0.001 then
            canBuild = false
            tile.Selection.SelectionBox.Color3 = Color3.fromRGB(255, 0, 0)
            tile.Selection.SelectionBox.SurfaceColor3 = Color3.fromRGB(255, 0, 0)
            tile.SelectionBox.Color = Color3.fromRGB(255, 0, 0)
        elseif b:FindFirstChild("Selection") and (b.Selection.Position - tile.Selection.Position).Magnitude > 0.001 then
            canBuild = true
            tile.Selection.SelectionBox.Color3 = Color3.fromRGB(0, 255, 0)
            tile.Selection.SelectionBox.SurfaceColor3 = Color3.fromRGB(0, 255, 0)
            tile.SelectionBox.Color = Color3.fromRGB(0, 255, 0)
        end
    end

Any help would be grateful :D

Edit: It only checks for the most recent child added to the folder, as of printing the magnitude.

Edit 2: I tried it with tables and the same thing is happening.