JC - I added your treasure chest into my cart and proceeded to checkout. Then in the box for the coupon code I typed in the ThankYou2013 code then applied it to my order. It said I received 10% off my order but would not allow another code to be entered. It would allow me to cancel that coupon code but I couldn't add another to it.
So you should be safe to have multiple coupons going all the time.
I'm glad to hear you have had success with some of your shows. A lot of getting our businesses up and running is getting known in the community - so yes, you did accomplish a lot.
Have a great evening!
Blessings,
Sandy