Bob Philips has a great page on SUMPRODUCT and double unaries '--'

He also has 2 ls in his surname, Welsh origins not Dutch <bg
Hello,

But he still does not show a SIGN() function around his example with
two OR criteria on that page <vbg

Compare
http://xldynamic.com/source/xld.SUMPRODUCT.html
[look for "=SUMPRODUCT((A1:A10="Ford")+(A1:A10="Renault" ))"]
to
http://sulprobil.com/html/sumproduct.html
[look for "OR Condition"]
and judge yourself.

Regards,
Bernd