It doesn't really make a difference, because the division he served in, the 10th SS Panzer Division, FRUNDSBURG, was never alleged to have committed a war crime or atrocity.
It is absolute fact that no one ever dug up war crimes against this unit. I think this ought to weigh heavy upon any negative cmments surrounding his time in service.
But the interesting thing I see is that he sat and waited...almost 60 years...to tell this story. After the Nobel prize and all of the German support of the past 60 years. The publisher was only going to print around 150,000 copies of the book...which probably got Grass a fair amount of income. But now with the media attention...there is a second edition of 100,000 additional books...and perhaps even more. Grass hasn't turned out alot of books in the past 20 years and I suspect that this is his last one and he is hoping to live off the income for his years to come. You have to remember....living in Germany society circles...it costs money and he isn't drawing the vast income that he did in the 1960's or 1970's. And with the mighty state-run broadcasting system helping to defend him in Germany...the guy comes off looking like the Pope...pure and clean. Almost amusing how he did this and got away with it in public circles in Germany.