Hello Ryota,
The value to convert from hex to decimal is actually 14Fh which gives 335d. This correlates back to the default VOUT_SCALE_LOOP value of 0.335.
The default shown in he register map table refers to the max value of Vref. the VOUT_SCALE_LOOP is a ratio of VFB/VOUT. Page 23 goes into more details about this and how to program the output voltage with this register.
Please note that the actual FB resistors should match the calculated values used.