Yes! I am on my second child and again using the Tupler Technique, and it really works. I can't believe how flat my stomach got compared to other moms that haven't used the exercises/techniques. The technique is actually something you've been doing since your teenage years, most likely. Remember going to the pool in your bikini and "sucking in" so your stomach looked flat? Essentially, that's what you do. You pull your belly button BACK towards your spine. All the way back as far as you can go is a 5. A 6 is an isometric movement.... essentially "clenching" or flexing that muscle once it's back at 5.
The Tupler technique is HARD WORK. But if you want a flat belly again, this is the way to get it. I do my exercises while I'm driving mostly. What I find the most challenging is completely relaxing my shoulders and legs while doing these "elevators."
Good luck... I hope you're seeing results. Love the splint too... now if I could just find it...