I forgot to post this when I originally found it, probably because some of these shield types were not enabled in stock FUSS at the time. They appear to be at this point, so in retrospect, best to point it out after all.

So in handler.c, function get_exp_worth( ), there are bonuses for shield types:

   wexp += GET_HITROLL( ch ) * ch->level * 10;
   if( IS_AFFECTED( ch, AFF_SANCTUARY ) )
      wexp += ( int )( wexp * 1.5 );
   if( IS_AFFECTED( ch, AFF_FIRESHIELD ) )
      wexp += ( int )( wexp * 1.2 );
   if( IS_AFFECTED( ch, AFF_SHOCKSHIELD ) )
      wexp += ( int )( wexp * 1.2 );
   wexp = URANGE( MIN_EXP_WORTH, wexp, MAX_EXP_WORTH );

All good and well, but half of them are missing...

    wexp += GET_HITROLL(ch) * ch->level * 10;
    if ( IS_AFFECTED(ch, AFF_SANCTUARY) )
      wexp += ( int )( wexp * 1.5 );
    if ( IS_AFFECTED(ch, AFF_FIRESHIELD) )
      wexp += ( int )( wexp * 1.2);
    if ( IS_AFFECTED(ch, AFF_ICESHIELD) )
      wexp += ( int )( wexp * 1.2 );      
    if ( IS_AFFECTED(ch, AFF_SHOCKSHIELD) )
      wexp +=( int )( wexp * 1.2 );
    if ( IS_AFFECTED(ch, AFF_VENOMSHIELD) )
      wexp += ( int )( wexp * 1.2 );
    if ( IS_AFFECTED(ch, AFF_ACIDMIST) )
      wexp += ( int )( wexp * 1.2 );            
    wexp = URANGE( MIN_EXP_WORTH, wexp, MAX_EXP_WORTH );

Hope someone finds that helpful!