I think that it is more likely that they received the new wafers...

I think that it is more likely that they received the new wafers around the Monday 21st May. Towerjazz are normally pretty close to the deadline and it may have slipped by a day or two.
Conservatively then, they have had the new wafers for a little over a week. This is the most likely representation of where we are at. We are then left to speculate how long it takes to "receive, inspect and validate" them. If we can assume that they have been received then how long will it take to inspect and validate them? Anyone prepared to timeline that part of the process?