  A recently developed reduced model of H-mode sustainment based on
interchange-drift-Alfv\'en turbulence description in the vicinity of the
separatrix matching experimental observations in ASDEX Upgrade has been
extended to experiments with the unfavorable $\nabla B$ drift. The combination
with the theory of the magnetic-shear-induced Reynolds stress offers a
possibility to quantitatively explain the phenomena. The extension of the
Reynolds stress estimate in the reduced model via the magnetic shear
contribution is able to reproduce the strong asymmetry in the access conditions
depending on the ion $\nabla B$ drift orientation in agreement with
experimental observations. The Reynolds stress profile asymmetry predicted by
the magnetic shear model is further extended by comparison with GRILLIX and
GENE-X simulations matched with comparable experiments in realistic X-point
geometry. The predictions of the radial electric field well depth and its
difference between the favorable and unfavorable configurations at the same
heating power from the extended model also show consistency with experimental
measurements.
