A few thouhts:
First is - I don't think there's a huge price difference with the 7s26 vs the 4R15. I know you can get a 7s26 for $50US, and maybe less. I wouldn't expect the 4R15 to be ten or fifteen percent more. Those are to the public prices, and wholesale will be less of course.
On the other hand, if very well could be that some very small makers are tweaking/adjusting movements as they're assembled into cases. So you might end up with something really nice and accurate with the unsigned movement - depending on the company thats assembling the watch.
Early reports of the 4R15 from users/wearers is that the movement is coming off the line very well regulated for such a entry level item. This could be because the assembly line is newer, has latest engineering. Or, that the line is newer, and everything is running as if it was just set up - tight and accurate, as opposed to the 7s26 line which is quite old.
I'd not mind having a 4R15 based watch, and keep in mind that the case is the dollar grabber in watch design - the movement is nearly secondary to fashion in most watches. You pay for fashion! I am old enough to remember when "dungarees" were the cheapest pair of pants a parent could put on kid. Then .... they turned into blue jeans, daily wear, and got fashionable, and ultra-fashionable. Pricing no longer follows common sense, and "fashion" pricing is set by good old fashioned supply vs demand.