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I am aware that this article might border on breaching Wikipedia's policy against unauthorised claims, but IMHO, facts about the Demetrii are in a contradictory state and Bopearachchi's identification simply does not match with a proper reading of Justin's account. I have stated my view about this on the discussion page of Demetrius III. Upon looking in Bopearachchi recently, I realised who Demetrius II looks like: Eucratides II. Same string of pearls, same orientation, even a common mintmark.
Alternative theories may be constructed: Eucratides defeated Apollodotus I (presumably Apollodorus of Artemita's text read something like "Apollodotus, brother of Demetrius (I), king of India") and was murdered by his son and co-regent, named Demetrius after the great conqueror. (No contradiction here. Cassander succeeded Alexander's brother, killed his son and still had his own son named Alexander.) And then Justin had the names confused.
The main problem with this alternate theory is that it gives Eucratides I no less than four co-regents: Plato, Eucratides II, Demetrius II and Heliocles I. But Plato does not easily fit in with the image of a co-ruling son, since he is obviously a middle-aged man, and if he is placed before Eucratides I but died after a short reign. This view is possibly supported by the latters introduction of the Dioscuri - a duo made up of one mortal and one immortal hero - which may be interpreted as "my dead brother and I".
So with Plato gone in the 160s BC that leaves three kings. And if either Demetrius II or Eucratides II died early, we still have one son who murdered Eucratides and one (Heliocles I) who avenged him.
None of this is of course material for an encyclopaedia. But IMHO no more contradictory than many other ideas about these kings.