In page 293 he explains.
Soundboard aggregates in cm2 = the size of the plantilla = the soundboard area.
BL X (UB+WW+LB) X 0,96
Bodylength multiplied with upperbout + waist + lowerbout divided with 3 and then multiplied with 0,96.
He worked out this equation with John Mack and it should give the soundboard area within margin error of 1,6%.
As you see: no soundhole mentioned.
So it is the entire soundboard area including soundhole area
and the area covered by the fretboard.
Hope this helps.
Antonio Marin nr. 813 1995 (Bouchet)
Vesa Kuokkanen 2016