Using Variables to Create an 'Inventory Survey'

Here is what I'm trying to do:

I have an inventory with 4 columns and 9 rows. 

In the paper Inventory, once the user has placed a ranking number (1-4) on each of the words, they are to ADD the numbers going DOWN the column (for some reason this creates complete CHAOS no matter how many trainers are in the room reminding them to add going DOWN... which is why we are looking to do it via an online module, so we can automate the calculations).

ANYWAY... 

For my online version, I have 1 slide for each ROW. There are 4 word items on the slide, and 4 ranking boxes. Users are to drag the word to the appropriate ranking box.

 

 

Each word is associated with a variable titled after the col/row from the paper inventory (which is how things are are counted). Example: Receptive is variable C1R2. Once each word is dropped on a ranking box (from 1-4), the user clicks next. Once NEXT is clicked, the variable values are changed based on which box they are placed on (ie. if it is on 1, the value becomes 1, and so on).

I managed to get all of the inventory questions set up properly. It was fiddly, but manageable. Here is the problem.

I am setting up the 'score' page (see image):

 

When users click on the calculator icon, it adds up the values for the column scores (see screenshot which is for the CE Score, button 1 above):

Setting up the calculation worked great. I was able to add the variables easily. Everything works great UNTIL I got to Button 4 (for the AE score). I found variable C4R1 in the variable list no problem, but no matter WHAT I do, it will NOT show variable C4R2 -- yet that variable is assigned to 'Impartial' (in the first graphic). 

So, I tried to 'add' C4R2 and it tells me I can't add it because there is already a variable with that name. If the program KNOWS that variable exists, WHY won't it show me that in the variable selection list on the scoring slide???

I didn't have this problem setting up any of the other scoring calculation triggers.

Any suggestions? I saved. Did a restart. Still no good. I saved as a new name. Did another reboot. No good. Took that button out and built it from scratch again. No good.

I'm out of ideas.

This is just the proof of concept version, and it was going great... until I reached this point.

Thanks in advance!