It would be interesting to track your shop for a month to see what you actually do. I'm cutting my own frame, and I'm not in the business. My times to be more like
45 minutes on the large tenon, 15 minutes on the unhoused mortise (I have a chain mortiser), and 30 minutes for a brace tenon, and I've not yet done a scarf joint. If I can do it in these times, anyone can. I did a short apprenticeship in a shop a few years ago. The joiners were all good. Some were very fast (too) and some were slower and more particular. But what I observed was a lot of down time. Talking about girls, talking about cars, puzzling over the strength of a timber, looking a plans to try to figure things out, waiting on timbers, moving timbers, etc. These guys weren't lazy by any means. They were just typical employees like most businesses have. Some spend time at the water cooler, and a lot of office employees these days spend a lot of time surfing the internet. It's rare in any business to find employees who keep their nose to the grindstone like the business's owners do. I guess what I'm saying is that you probably need to take your ideal day (16 joints a day on average) and multiply it by a factor (60%?) to get an accurate frame estimate.