According to the constraints specified in the data sheet for the LT8330, the SEPIC inverting converter voltage output can be no greater than half that of the non-inverting boost converter.  At least, this is what I read considering the limits that can be used in the FBX voltage divider resistors.

I need to generate -48V (from +12 in) and it need not supply much current - it's used in an electrostatic application.  I've already configured a design for its opposite, a +48V boost, which fits into the FBX range without any worries.  

Oddly, the LT Spice model, using the standard values on the data sheet for a -24V converter, achieves only -14.5V.

Can the LT8330 be extended to -48V out by exceeding the FBX limits and achieve a reasonably stable voltage?  (+-0.1v is fine here, plus noise).  Or, are there better solutions?