how much

food should I be consuming 20 months out??  Sometimes I feel like I can eat too much.  I am eating healthy and still stay away from pasta, rice and bread and eat lots of protein.  Its the amount of food that I am consuming that has me worried.  i can eat 1/2 a sweet potato at one time which I think is a lot. 

I'm two years out ds and I can eat half a steak and half a potato. That sounds normal to me.

I'm a little ahead of you and I have noticed that I can eat a lot more, too.  I can pretty much eat a small/normal size meal.  I'm not worried about it.  I don't think the surgery was intended for you to only be able to eat a few bites for the rest of your life.  While I am glad that I am satisfied with a much smaller amount of food then I ever was, I think the point is to use the time right after surgery, when the restriction is greatest, to loss the excess weight and learn to eat smaller amounts and healthier food.
I look at it this way.  There are plenty of naturally slender people with normal sized stomachs so having a tiny stomach isn't necessary for success.  It is what I eat as much the amount that matters.
It seems pretty common to question the size of your stomach.  If you are happy with your weight loss/maintenance then  you are doing something right.  If you are concerned you could always make an appointment with your surgeon to discuss your concerns and where he thinks you should be at this point.

 Your full size stomach was about the size of a two liter bottle of soda.  Your new baby pouch was about the size of the bottlecap on that soda.  Your pouch grew to about the size of large egg and holds between one and one and a half cups of food.  That would easily hold half of a sweet potato.    The trick now is to figure out what you need to eat to keep your weight from coming back.  That usually starts at about month 30 so you will might have some honeymoon where you eat pretty much what you like and don't gain.

Keep doing what are doing and if you have not done it yet, add a daily weigh in to your routine.  The bounceback regain phase after RNY is normal and it is easy to let it get out of control.  Daily weighing is the way to stay out of denial.