The *sg28ref is the post call for G28. Some people change the define statement in the post where it is G28 to G30. Problem is then they want G28 and lose it. You see you need both. So you can either make a correct change where you make it *sg30 and get the G30 always when you need it and then in the post where the G28 comes out you can then see if you get what you want. I am thinking you may have to add some logic and that is where you really should contact your dealer. Hopefully that is a enough to get you started on the right track if you are so inclined to not contact your dealer.
pl_retract #Retract tool based on next tool gcode, lathe (see ptoolend)
cc_pos$ = zero
if home_type = one,
pmap_home #Get home position, xabs
ps_inc_calc #Set inc.
pbld, n$, psccomp, e$
pcan1, pbld, n$, *sgcode, pfxout, pfyout, pfzout, *toolno, e$
pbld, n$, pnullstop, strcantext, e$
#Retract to reference return
pbld, n$, `sgcode, psccomp, e$
if home_type = m_one, pbld, n$, *toolno, e$
pcan1, pbld, n$, *sg28ref, "U0.", [if y_axis_mch, "V0."], "W0.",
pnullstop, strcantext, e$
if home_type > m_one, pbld, n$, *toolno, e$