Subcool doesn't do feminized. DNA/Reserva Privada are basically the same company and they are fine too.
Yes, flowers still develop on a seeded plant. But lets step back a second. It's best not to have any seeds cause 1) once a plant is seeded, it stop wasting it's energy on bud production and starts on seed production so less quality, and less bud weight. Ideally, you want a bud to properly finish all the way so it maximizes it's resin production. Seeds are also a pain to sift out of a bud. I've seen total bud weight as much as 80% seeds too.
Many companies do produce feminized seeds that don't hermie at all, unless you really stress the plant i.e. light leaks, too hot in the room, over dose of fertilizer, not watering properly, too small a pot for the plant, etc. The company's I listed seem to use a different process to produce their beans and often don't have problems but others like i.e. Dutch Passion, Nirvana and Mr. Nice come to mind first for constant hermie problems. The 2 strains I am doing most now, Sweet Seeds "Green Poison" and Next Generation "Grape God" have not produced any male flowers at all after numerous grows of them. They are both very stable.
Lastly, I have some friends who prefer a little seedage in their buds cause it helps the plants finish off well and quickly and gives the plants a richer, fuller smoke. Personally, I like to find `1 seed per plant for future use, since they often are females.