1) RoHS The Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment 2002/95/EC is more commonly referred to as the Restriction of Hazardous Substances Directive or RoHS. You can find the basic information on this at Wikipedia at en.wikipedia.org/wiki/Restriction_of_Haz..._Substances_Directiv
The directive restricts the use of the following six elements and compounds: a) Lead b) Mercury c) Cadmium d) Hexavalent chromium e) Polybrominated biphenyls (PBB) f) Polybrominated diphenyl ether (PBDE)
2) Code-Designation for Power Cables with PVC or XLPE Insulation
i) Conductor Design N According to VDE Standard (No abbreviation for copper conductor) A Aluminum conductors
iii) Concentric Neutral and Shielding Design C Concentric conductors of copper wires and copper tape, helically wounded CW Concentric conductors of copper wires in wave conal formation and and copper tape, helically wounded CE Concentric conductors of copper wires and copper tape over each individual conductor, helically wounded
iv) Shielding S Shielding of copper wires and copper tape, helically wounded SE Shielding of copper wires and copper tape over each individual conductor, helically wounded (F) Longitudinally water-proof shielding
v) Armor B Armor of steel tape F Armor of galvanized flat steel wires G Counter helix of galvanized steel tape
vi) Jacket Y PVC jacket
vii) Outer Jacket Y PVC jacket 2Y PE jacket
viii) Additional Designations for Cable for U0/U 0.6/1 kV -J Cables with green-yellow (green-natural) conductor are marked with protective conductor -O Cables without green-yellow (green-natural) conductor are marked without protective conductor
NYCWY - VDE Standard copper conductor - PVC Insulation - Copper Wire Concentric Neutral Conductors Applied in Wave Conal Formation (Ceander) and Copper Tape, Helically Applied - PVC Jacket
Since the minimum bending radii, the flexing temperature range and the fixed temperature range are the same for both cable designs, it would seem to me that your question has become:
"When are wave conal or ceander concentric neutral conductors along with helical copper tapes specified instead of helical concentric neutral conductors". I will leave that question for power cable product design engineers to answer.
From the manufacturing perspective, the acquisition of the equipment for the application of wave conal or ceander concentric neutral conductors is cheaper than the acquisition of a concentric neutral rigid strander, especially if a large number of conductors is involved. However the application of the helical metallic tape to contain the wave conal conductors would seem to me to make the cable more costly in terms of materials.