  Mass-dependent quark contributions are of great importance to DIS processes.
The simplified-ACOT-scheme includes these effects over a wide range of momentum
transfers up to next-to-leading order in QCD. In recent years an improvement in
the case of neutral current DIS has been achieved by using zero-mass
contributions up to next-to-next-to-leading order (NNLO) with massive
phase-space constraints. In this work, we extend this approach to the case of
charged current DIS and provide an implementation in the open-source code
APFEL++. The increased precision will be valuable for ongoing and future
neutrino programs, the Electron-Ion-Collider and the studies of partonic
substructure of hadrons and nuclei. A highly efficient implementation using
gridding techniques extends the applicability of the code to the determination
of parton distribution functions (PDFs).
