=SUMPRODUCT((A5:A504="Permanent")*AY5:AY504)

Colmun A cells can either be blank or hold data in sets of 4 rows i.e.

a1 will be "=con1"
a2 will be either "Permanent", Associate or Contractor
a3 & a4 will empty

this then repeated for next 4 rows etc changing the "=con?" for each set
upto "=con100"

Column AY cells will hold the value of a calculation i.e. "=ad5" or be blank.

In essence what I am doing is totaling the values (ay cells) for each
category of "Permanent", Associate or Contractor

Strange point is that if I have the "Permanent", Associate and Contractor"
listed in the cell before the "=con?" i.e. swap a1 and a2 around cell the
above formula works otherwise no calculation is done?

As ever any questions please ask but many thanks in advance.

Ukman