I understand it like so: (not a native speaker myself) individually, they both give 2 criteria. Together, they would give 4. (So, say, the 1st one gives criter

I understand it like so: (not a native speaker myself) individually, they both give 2 criteria. Together, they would give 4. (So, say, the 1st one gives criteria #1 and #2, and the second #3 and #4)