I, for one, have install customers that are using discharge with the LED bars and have been with no issues. I can say, "They love, love, love them". That is with various emulsion brands. They typically do not change emulsions due to having an STE installed. Most like what they use, not just for exposure times, but for other reasons like durability ets. That alone, says that they are good with what they (have been) using for emulsions and their choice for emulsion has little to do with the LED lights itself. We know that some emulsions are faster or slower and over time, can make a $ difference, but more often than not, the customers stick with what they have been using. In other words, our LED's work with what they (the customer) prefers to use.
If some change emulsion for any reason, it would be after I've long left and they decided to try something else. That might be for less cost or faster times or more durability. I wouldn't know, as I don't have any info on my customers actually doing so.
I cannot provide any info on stats for quantities per a single order. We don't really need to focus our attention to our customers average quantity per order. Just the total screens done per day on average.
I would think the strength or lack thereof, comes from an emulsion itself, and not the intensity of the LED's or type of light used to expose. A properly exposed screen...is a properly exposed screen as one might say. Once it's "properly exposed" it's reached it's optimum point of what the light source and time can do. The "life" of that screen may rest in (the emulsion), or rather (the stuff that's in it). I could be wrong on that. There could be more too it than I see on the surface. It seems to make sense thus far.
Emulsion "durability" over long production runs may not be a focus for many printers due to other reasons beyond just durability. For most shops, for example, a 10,000 piece order does not come along every day. Maybe the big shops do 1-3 a week if they are lucky. Much of that is all speculation but we all know of (some shop) out there that is said to do 10,000 (on average). Hard to imagine, but there are some. How much of that (is with dual cure) is another question.
For the more common large volume print shops that might do one-10,000 order a week if they are lucky enough, I would say that the multiple benefits of using LED for the remaining orders in the week...far outweigh the cost of changing out screens at the 5000 mark (for a 10,000 piece order) of one job per week. That is an (if) they need to. I don't know. Like you, I don't have any feedback on that yet. It's an interesting question tho. I would like to hear more on that if you gather any additional info.