  We study the Large $N_\text{c}$ scaling of pion-pion scattering amplitudes
for $N_\text{f}=4$ degenerate quark flavors. We focus on the standard isospin-2
channel and the adjoint-antisymmetric (AA) representation. The latter only
exists for $N_\text{f}\geq 4$ and a representative state is
$\frac{1}{\sqrt{2}}(|D_s^+\pi^+\rangle-|D^+ K^+\rangle)$. We compare the
results obtained for two regularizations (Wilson and twisted-mass fermions) and
three values of the lattice spacing, and observe significant discretization
effects in the AA channel. Finally, we match our results to NLO SU(4) and NNLO
U(4) Chiral Perturbation Theory and constrain the $N_\text{c}$ scaling of the
relevant low-energy couplings.
