ommam, shake the lisp language to move objects to their origin?
and then it could work if (and I say if) the basic var. was different from zero.
you can safely have entities to x 1 million, y 1milione and have simultaneously insbase=0,0
to answer your questions, a viewport is defined according to the coordinates globali, at the time of creation, regardless of the ucs (which can also be a local ucs). if you move objects into the model, it goes from itself that the viewport no longer frames objects, which are now in a new position.
You should intervene via lisp to transform the global coordinates of the viewport in the new coordinates that take into account the shift you have made, and do this for each viewport.
if you put on a rotation of the axes... you should rotate both objects (in the model) and viewports (in the layout)
possible yes, long list also.