ABAQUS (6.8, 6.9 EF) - Effect of the number of back stresses

Since ABAQUS 6.8, a new feature has been added to the combined hardening
material input.

Let's assume a combined Kinematic and Isotropic hardening case, such as
those happen in metals.

"Half cycle" uni-axial test results has been utilized to model the yield
stress-plastic strain behavior as well as the Kinematic behavior of the
metals.

In the same user interface,  there is an option to choose the number of
back stresses.

Is the number of 1 back stress is equivalen to the case of linear
kinematic hardening (Ziegler's)?

Similarly, does it mean higher values for the number of back stresses
trigger nonlinear kinematic hardening in the ABAQUS model? If so, does
it mean using higher values for the "number of back stresses" option
when half-cycle input data has been used, more closely predict the
kinematic hardening behaviour of metals/models?

Thank you,

Ron.