The FE-cross sections at a segment point are unique defined by their original cross section and the list of current values for the variables.

When a re-calculation without formula evaluation is chosen, the FE-cross sections will be updated using the existing variable values. This kind of calculation is faster than one with formula evaluation and it is sufficient while the used formulas and tables (symbol f(x)) is not changed.

When a re-calculation with formula evaluation is chosen, the FE-cross sections will be updated after the mathematical expressions have been evaluated and if necessary, new FE-cross sections will be created.  This kind of calculation is slower than one without formula evaluation and it have to be done only if any formula or table has been changed.