When you are trying to lose weight/fat , weight lifting should be seen as a way to preserve or gain muscle. Not as a fat loss method.
So your question is irrelevant.
And even if you wanted to use weightlifting as a fat loss tool (which is a mistake) there are variables that have a lot more impact on fat loss than tempo, like volume, rest intervals, training method.
In the grand scheme of thing the difference between both tempos will not be significant at all.
In theory the 4120 tempo would burn more calories because a set lasts longer so your burn more fuel BUT the slower eccentric can create more inflammation, which makes the muscle more insulin resistance, which can make it harder to lose fat. In theory the 4 seconds eccentric should help you retain more muscle because it activates mTOR more, BUT you will also use less weight and I believe that keeping your strength up when dieting down is key to avoiding muscle loss.
I'm only saying this to illustrate that in the grand scheme of things the tempo you select will not make a significant difference in fat loss.
You are overthinking this.