Good morning.
In level 4, the experience needed is:
[tex]\mathsf{g(4) = 7\cdot3^{4-1}}\\ \\ \mathsf{g(4) = 7\cdot3^3 = 7\cdot27}\\ \\ \mathsf{g(4) = 189}[/tex]
In the hardest settings, the multiplier is:
[tex]\mathsf{h(4) = 4\cdot 4}\\ \\ \mathsf{h(4) = 16}[/tex]
So, the adjusted experience points are: multiplier . base experience
[tex]\mathsf{E(x) = h(x)g(x)}\\ \\ \mathsf{E(4) = h(4)g(4) = 16\cdot 189}\\ \\ \boxed{\mathsf{E(4) = 3024 \ points}}[/tex]