Warhammer,
I just got off the phone with a friend over at Aqualung/SeaQuest whom is the Manager of Technical Projects. He offered alot of great info about the Apeks inquiries you had. It turns out that these regulators were originally designed to go through stricter CE tests in Europe. They were designed to handle colder waters.
Here in the US though, the consumer puts more emphasis on Work of Breathing or what's called the Breathing Loop or Curve. The effort that it takes to get the air to begin to flow is called the Cracking Effort. When you look at a regulators performance graphs, the spike is the cracking effort. Anything more than .8 is considered to be hard on these shores.
Here in the US technitians have been reducing the cracking effort by swapping out a part. When the Counter Balance Cylinder is shortened it relaxes the spring, which reduces the effort. From what I understand, this doesn't change the WOB, it just flattens out the spike a bit, making it feel easier to breath. From my understanding the units being shipped since Aug are shipping with the Counter Balance Cylinder shorter... which means your shop might have older stock.