I am pretty confident that you are seeing the industry trend toward "cost reduction" in kits.
Until about 2004, quality was consistent. Then, some products became available from Chinese manufacturers. I was one of the "early adapters" who wanted to see the cost of kits come down, so I bought LOTS of slimlines that I knew were Chinese made. They bent as they were assembled, the tubes were not consistent, they did not "click" into a position, but I continued to buy them, hoping that, with experience, their quality would improve.
I believe it HAS IMPROVED. HOWEVER, the quality is still not as good as the transmissions made by the Taiwanese sources.
When we decided Exotics would sell pen kits, I had several lengthy conversations with industry sources. Jim, president of Berea, assured me he was going to continue his relationship with his Taiwanese partner and not experiment with Chinese. (Jim was in the industry in the early days and remembers when ALL transmissions had problems and tolerances were all over the map--he has lived the "this doesn't work right" experience and did not see a reason to repeat it.!!)
So, that is why I chose to handle Berea's kits. They are consistent! You know what you are getting!
Currently, my slimlines (through Exotics) are NOT Berea. I realize that most penmakers buy price. So, we are selling competitively-priced slims, with some components made in China--I suspect.
I will be adding Berea slimlines in the next 90 days--pen and pencil. Main reason is people want "sets" for the holidays and I don't want to sell Chinese pencils.
For those who will scream this is an ad, let me add this:
I buy tens of thousands of dollars in pen kits. I can buy from ANYONE, and do. So, if I HANDLE the product, I will tell you if it is the BEST, or a compromise between quality and price. Our slims are compromises. I will soon be stocking Berea's, with which I have NEVER had a problem, in 10 years of selling at shows. That is not advertising, that is relaying my experiences----BEFORE I was a part of ExoticBlanks.
You are all giving your experiences, I see no reason why my experience is not equally valid. Those who disagree, feel free to PM me.