Sandwich model theory in SAP2000

[BOCH]

Hi guys,
The design of shell elements in SAP2000 is based on the sandwich model theory, which is cannot be applicable in case the core of the sandwich model is cracked due to transversal shear, in this case the formulas of the theory changes by accounting for an additional tension force in the longitudinal bars, This is shown explicitly in SAP design manual.
However,
According to ACI code, transversal shear never affects the longitudinal reinforcement of a beam or slab section, so even if a slab is cracked under transversal shear, the longitudinal reinforcement remains same.
According to Eurocode, transversal shear affects only the curtailment length of the longitudinal bars and not the amount of As longitudinal, so if a slab is cracked due to transversal shear, the curtailment length of the longitudinal reinforcement is affected only.
So,
What is the difference here ? Can we explain this by the following, "in case the core of the sandwich model is cracked due to transverse shear, an additional force that affects the curtailment length of the longitudinal tension bars should be applied" ? And what would be the situation is case of ACI code ?
Does anyone have an idea ?
Thanks ...