Tests has been made, that says about possibility to write DL media by NEC 2500@2510. Now it is a good time for waiting another firmware and another DL burns. I am sure, that ALL WILL BE OK! Error rates still lower than specified in the specs in burns, that we saw.
They talking about adjustments... That is really funny. They will NOT change anything, because of the price of changing. Cheaper to make entire new model with different OPU and different speed formula, market will be happy and money will come to NEC.
In this case - they using EXACTLY the same model, economy and DL is possible.
2100, 2500 was planned as long-life model. Yes, it, really, is.