List Vars and Uniques Exceeded

How does (Low Traffic) logic work with List Vars?

Will list var values be bucketed into (Low Traffic) or Uniques Exceeded when more that 500,000 unique list var strings are received, or is it 500,000 per list var element?

My list var looks a bit like:

an=00;sx=CYY;xv=6221;ik=9;ab=1;za=1;zc=1;ze=1;zg=1;ar=50026;al=102;aq=1;as=1;ul=AFWBVVXQRX;ef=2;gh=NCY;dh=HW;ia=FD0D9E7;kp=1;tn=C196325D67968E84;ut=1;po=044062

An I will be delimiting on semi-colon. We get around 2.5 million unique values per month. I plan to classify each key value pair, but would like to understand how Low Traffic logic works with list vars first.