@Julia DH
Hopefully, someone who has had "direct experience" will reply. But, unfortunately, many folks who pay 7k for something tend not to be objective, and will be likely to tell you how great it was! :-)
As per my previous reply, it seems like a plausible program... if you want two high school diplomas. The partner institutions appear credible, and it seems to be accredited. It's been going for many years, and has lots of students. There are no red flags for me. What have you spotted that makes you concerned?
In terms of its utility, I already tried to address that. It's just one opinion, of course, but you only need one high school diploma to get into university. So what's the point of a second one? It's probably interesting and there might well be cultural benefits... but it's extra work (for your daughter, not you). As I suggested, better to put extra work into one high school diploma and better grades... rather than two diplomas with mediocre grades. If your daughter is supersmart and you think she will get all As in both... then I still don't see the point! :-)
The extra hoop for foreign (non-Anglophone) students (applying to English language education whether in UK, USA or elsewhere) is the language proficiency. A test (IELTS or equivalent) will almost certainly be required. If you have a US high school diploma (which is an education in English), it's possible that this could be accepted instead (but I doubt it, because it's not a full-time program in USA). In any case, if your daughter is already bilingual then a 7k HSD is a very expensive way of proving this! :-) She could probably take the IELTS tomorrow, and get a good enough score to satisfy a university - and for a lot less money and time.
What universities look at is grades, principally. So lousy grades = bad. But many universities are very competitive, so perfect grades (or near-perfect grades) are merely necessary, but NOT sufficient. You then (especially for USA schools) have to top this up with fantastic application essays and stellar extracurriculars. Again, the time spent on a 2nd diploma leaves less time to work on these things.
Finally, as I noted, many/most USA universities require standardized tests. This is a LOT of work. There's no point have great grades, but a lousy standardized test score. Last time I did this, I spent MONTHS on it. That's because everybody can do OK... so the only way to get some visibility is to be 98th or 99th percentile, and that takes serious work, even if you're a top-of-the-class student.
As to applying in Europe, they'll all be happy with a Spanish HSD, so again a 2nd one is superfluous. (But if it's a German degree, for example, then a language proficiency test at B2 would probably be required.)
As a wild guess... maybe this is more to do with your husband being American, and your daughter being bilingual. Americans, generally, seem to imagine that their education is the best in the world. So perhaps you're heading down this route because you have been convinced of this too?
Don't get me wrong: if your daughter can get into Stanford or MIT or Harvard, it will be a real feather in her cap, and great for her career.
But what USA education certainly is (like USA medical treatment): the most outrageously expensive in the whole world! Whereas, some EU countries (e.g. Germany) even have free tuition, and most of the others are not expensive. If you're concerned about 7k euros... wait until you start looking at the 50k per year to go to a US university. :-)
Plus, they are insanely competitive to get into, just have a read on the internet. You need ALL the stuff I referred to above. And it's just a HUGE amount of work.
But, let's say your daughter is a Gilmore Girl, and she has her heart set on Harvard. :-) AND you have the money to pay for it! Then, of course, you need a plan for how to build the best possible application package. You need a 4.0 (perfect grades), and a 99% percentile standardized test score, plus great extracurriculars and a compelling application essay. Only an admissions tutor can tell us how much value they would attach to 2nd HSD, but my suspicion is very little, sorry. :-)
If you're serious (or your daughter is serious) about a USA university application, you have to do what they want... not what you think they want. :-) There's loads of info online that will confirm what I'm saying you need.
Unless your husband is a graduate of Harvard or Wharton or MIT or somewhere equivalently stellar. Then there is a big family preference that kicks in, so your daughter's chances shoot up. But you still need the grades and the standardized test, it's not a freebie. :-) Leaving this aside, you're dealing with the sheer volume of applications (from outstanding candidates) and the ridiculously low acceptance rates... maybe 5% ish? European universities (even the very best in Spain and Germany and UK) are probably a lot closer to 20%. With a lot less work for each application.
Writing this is bringing me out in a cold sweat thinking about when I did this. What a nightmare!
And after all that work, when I got accepted... I ended up declining my place!! I went... you want HOW MUCH??!! It was around $60k (and this was 20 years ago) per year x 2 years (master's not a bachelor) PLUS big city living expenses. Or 10k per year x 1 year at Oxford, instead? With small-town living expenses, including subsidized student accommodation. It wasn't a tough decision. :-) Of course, in hindsight, I can see that it would have been very cool to have an MIT degree, especially after doing all that work to get accepted... and I probably would have had much better jobs in the years after. But I don't regret the decision, an Oxford graduate degree is not such a terrible outcome.
