The very image and text used in the article implies that the original poster is correct.

Look at the example for 32 - it is given as 8 + 2x12. The hand on the right has two fingers extended. Clearly all fingers can be extended in this image, and then the number would be 8 + 5x12 = 68. If the left hand is used to count to 12, the number is 12 + 5x12, or 12+60=72.

Either the limit is 60, or the images/text in the article are wrong.