Forget the help and what grades your kids get, and activities outside of school.
So 1/3 of the year, you'd both be potentially working 12 hour days - and is there a commute? I would just be very realistic. There's meal prep and all the extra stuff (laundry at night, errands to run. .) that you're probably doing during the day. It's busy.
I've done both. Of course, most people don't have the choice. So people make this happen and kids thrive either way. Most kids don't know what it's like to have a mom home. I agree, it's great for kids to see mom fulfilled. I'm home due to circumstances a lot of the time and I miss it too when I'm not working.
The thing is, I have found that older kids require parents to be around just as much, if not more (college prep, talking about futures, going for part time jobs, girlfriend troubles, etc.) than younger kids who just need help setting up playdates and shuttling to activities. There's a whole lot of listening and the odd bit of guidance.
One of mine said that he liked I'm just here. That shocked me - and I think working moms of course can be there too - they don't have to be home during the day, but if no one is home in evenings for long stretches ... or they're wiped out (understandable if you're both going full tilt) ... it's a busy time is what I'm saying - those teen years.
You may find you're busy when you go back, and your hubby's position may intensify as he moves up in his career. Just consider that.
It sounds like a wonderful opportunity - I'm just pointing out some possibilities. I think it does sound terrific, and I'm sure your kids can handle it. There's always weekends, and other times to get stuff done. Kids can help out too and that helps them learn responsibility, as I'm sure you're already doing :)
Mine are a bit older (my older ones) - so just sharing that I find our lives are busier than I expected.
If this is the first offer you've had, just wondering if you might find something that could be a better fit? Or take this and keep your ears open if it turns out to be too hectic?
I guess you know your family and just weigh the pros and cons. If you don't have a long commute, maybe it's very doable. Maybe the kids will be in activities and it won't make much of a difference anyhow.
Good luck :) Congratulations on the offer!
ETA - saw your SWH. Sounds like wasn't quite the right 'fit' but good to know there are opportunities out there, and must be good to know that, and good experience to interview :) The right thing will come along, and now you're prepared for it when it comes!