ah yes, options are often simulator specific. We also support hspice and that has a different .OPTIONS line:

if OPTS.spice_name == "ngspice":
            # ngspice sometimes has convergence problems if not using gear method                                                                     # which is more accurate, but slower than the default trapezoid method
            # Do not remove this or it may not converge due to some "pa_00" nodes
            # unless you figure out what these are.
            self.sf.write(".OPTIONS POST=1 RELTOL={0} PROBE method=gear\n".format(reltol))
        else:
            self.sf.write(".OPTIONS POST=1 RUNLVL={0} PROBE\n".format(runlvl))