Do not worry, it is not about the quality of the glass
2 days ago I ordered my Da12-24 and the shop owner promised me that I can receive it today.
I went to the shop with excitement and ... it was not there.
He called the distributor and learned that it will be available on 18th. When I was willing to cancel my order, he talked with the dist again and hopefully I will get it tomorrow....
I though Japanese people are very strict in their promises
But the good part of the story is that, while I was waiting for the phone calls, I learned that there is a "Pentax Photo Trec" (Photo exhibition) in Nagoya-Japan. If anybody is interested I can provide the details of the exhibition.