99$ courses

What I have noticed in the past.

If I had a coupon (say $99.00) for a course and found one I wanted in the store. Often adding the course to my cart then adding the coupon would not change the price.

However...

Often there would be a page for the $99 sale listing "Some of the courses that can be had for the $99 price. But you say, that's ok but the one I want is not listed on the sale page (grumble)! Look at the bottom of the sale page and you will likely see a link that will allow you to browse "More" choices.

If you follow the "More" link and look for your desired course, find it and add it to the cart now, the sale coupon will most likely work as needed.

I guess my point is for some sale coupons to work you have to use them directly from the sale page (or by following a link from that sale page), not just directly from having preformed a site search or say looking at ALL courses. 

You would think that the coupon should simply work but sadly it does not always do so.

So back to your course LA181. If you have the coupon in an e-mail, try following the link to view available courses, from that mage try to find a "Look at more courses" link, follow that link and try to find the LA181 course, add it to your cart, apply the coupon and see if the cart total adjusts down to $99.

That will directly give you your answer. As long as you don't  actually complete the purchase, you will not have "Redeemed" your coupon yet. (at least in my experience so far).