longitudinal bend test . Asme Section IX. Welding qualifications.

[mcrespo]

My question is, according to ASME section IX, if we are going to qualify a welding procedure with 

a stainless steel base metal (P number 8) with a carbon steel (a P number 1), using a stainless steel filler metal . 

Is it necessary to make longitudinal bent specimens to qualify the procedure?

See  QW-161.5 Longitudinal-Bend Tests."Longitudinal bend tests may be used in lieu of the transverse sidebend,

face‐bend, and root‐bend tests for testing weld metal or base metal combinations, which differ markedly in

bending properties between (a) the two base metals, or (b) the weld metal and the base metal"

Are the differences beetween these to metals considered markedly different? 

If in the previous example it was decided to use a Nickel electrode which differs in ductility from carbon steel, would it be necessary to do longitudinal bent ?

I am preparing to the certified welding inspector exam in my country. 

Regards,