Converting to higher Symmetry [CASTEP]

Dear All,

I know that, when creating a crystal Supercell, the symmetry relationships between objects are redefined and the new structure will have P1 symmetry. But when running calculations a prompt message (screenshot attached below) asks whether to convert to a higher symmetry (which significantly improves the calculation speed) or to stick with current P1 symmetry.

Which option to select please? My calculations are on substitutional doping of a crystal supercell.

In the documentation of Materials Studio it is written that:

"For many simulations it is necessary to convert a given crystal structure to a lower symmetry description. [....] It may also be useful to define a supercell or reduce the symmetry in systems with interstitial or substitutional disorder such as doped semiconductors, ...."


then if it is necessary to lower symmetry for such calculations to be possible, why and how is it possible to raise back symmetry and run the simulation?

Regards.