You can go to China and secure a good source, I know of some guys who have done it, but in the end, it doesn't mean your source won't try to slip you a fast one. Chinese are known for this, not only when it comes to steroid powders but other businesses as well.
The problem is that most UGL operate on a small production scale. If you have 40 different products for sale, and are buying small powder lots of 100-500g or so, chances are you won't be testing every product. You'll notice that most large companies have a smaller selection of products.
Let's say they make products on a 1kg scale, well that's only 400 vials for example. If they did things on a 25kg scale, it would be a different story as quality control would be easier to maintain. Testing a 25kg drum would cost the same as testing a 100g pack of steroid. Imagine testing 40 different lots. At $500 at pop, you are looking at $20,000!