Tried a number of different combos on LNCC.
Finally got it to work. Cleared my cart (thanks for the suggestion), signed out, added GATs, added code, signed in, checked out.
Although one of my tries earlier it seemed to recognize the code and discounted it but it eventually undiscounted itself.
My total came out to 274.96
So it looks like it is slightly more than the 44% off it stated.