Yes, kinda. Haha! It's hard to explain - you still want a bend in your knee, but the lower part of your leg should be mostly fully perpendicular to the ground with your foot parallel with the ground. I hope that makes a little more sense, hehe...
...When I am bouncing in the saddle like crazy, asking him for a lope and sitting in the right position for it - it is really hard to ask him up again from that trotrotrotrotrotrtortorotrotrot he has...
I have no idea why anyone would WANT their foot parallel to the ground while galloping or cantering. I'm not saying it is always wrong to ride with a level foot. It isn't. But all other things being equal, I don't see a level foot as a big advantage that someone should try to achieve.
If your heel is under your hip, then your lower leg is angled back and a level foot is often all a person can do. If the heel is further forward, and the lower leg is vertical, then it is easy to allow your weight to flow past your knees and into your heels, and have the heels lower.
I'm not a teacher, trainer, champion anything. I don't compete & I only have a bit over 5 years of experience. But personally, my leg is more stable and I find it easier to keep my feet in the stirrups when my heel is just in front of my belt buckle and my heels down.
If you are bouncing like crazy, then something is not quite right. With me, bouncing is usually due to one of two things:
1 - I have a stiff lower back from a fall 4.5 years ago. Some days it isn't too bad, and I can move well with the canter. On other days, it hurts, is stiff as a board, and I use a half-seat to save my horse's back. A stiff lower back and sitting the canter don't go well together.
2 - My horse is balanced too far forward. She is getting better, but she has always had a habit of cantering with her balance dangerously far forward. When we started, I literally was scared we would flip over. She is learning to canter with better balance, and we are doing lots of circles at a trot to help her balance...but when her weight goes too forward, she is a rough ride.
There are probably a lot of other causes of bouncing. Those are my two biggest problems.
Sitting the canter or gallop is fine if you move well with the horse. Given my back, I often prefer a half-seat. Here is an old thread on it, from an English/forward seat perspective: Riding the canter in half seat
If you want speed, then a forward seat (including western riding) helps a lot. George Morris's book on Hunt Seat Equitation is great. Although he writes from a jumping perspective, the principles work fine with a western saddle on the flat. At least, they have done well by me.
This is a good, short article: http://ezinearticles.com/?The-Riding...ter&id=2277803