datevar t:=date({Orders.Ship Date});
if t in
dateadd('d',8 - dayofweek(date(year(t),3,7)),date(year(t),3,7))
to
dateadd('d',8 - dayofweek(date(year(t),11,1)),date(year(t),11,1))
then
dateadd('h',4,{Orders.Ship Date})
else
dateadd('h',5,{Orders.Ship Date})...