Modifications of the non-linear Schrödinger model (MNLS) i∂tψ(x, t) + ∂ 2x ψ(x, t) − [ δV δ|ψ| 2 ]ψ(x, t) = 0, where ψ ∈ C and V : IR+ → IR, are considered. We show that the quasi-integrable MNLS models possess infinite towers of quasi-conservation laws for soliton-type configurations with a special complex conjugation, shifted parity and delayed time reversion (CPsT d ) symmetry. Infinite towers of anomalous charges appear even in the standard NLS model for CPsT d invariant N −bright solitons. The true conserved charges emerge through some kind of anomaly cancellation mechanism, since a convenient linear combination of the relevant anomalies vanish. A Riccati-type pseudo-potential is introduced for a modified AKNS system (MAKNS), which reproduces the MNLS quantities upon a reduction process. Two infinite towers of exact non-local conservation laws are uncovered in this framework. Our analytical results are supported by numerical simulations of 2−bright-soliton scatterings with potentialOur numerical simulations show the elastic scattering of bright solitons for a wide range of values of the set {η, ǫ} and a variety of amplitudes and relative velocities. The AKNS-type system is quite ubiquitous, and so, our results may find potential applications in several areas of non-linear physics, such as Bose-Einstein condensation, superconductivity, soliton turbulence and the triality among gauge theories, integrable models and gravity theories.