Should this pipe need to do flattening test ?

Do 508=A1=C142, material is 15NiCuMoNb5, PO standard is EN 10216-2
In the mandatory test section of table 13 of EN 10216-2 , it says that
"Flattening test for D < 600 mm and T/D ratio =A1=DC 0,15 but T =A1=DC 40 m=
m or
Ring tensile test for D > 150 mm and T =A1=DC 40 mm"
I don't catch the meaning of the word "but " , I think pipe whose
wall thickness more than 40mm has no need for Flattening test. Because
the wall thickness is too high to do Flattening test But these tests
are mandatory. I am confused