Why 74%?

6 and 33 are both in the heart family (3, 6, 9). 33 is a master number, so it is matched as its root, 6. The same root number twice starts at 76. The nudge comes from the roots: 6 + 6 = 12, which leaves 0 when divided by 3, so the nudge is −2. 76 − 2 = 74.

Out of the 78 possible pairings, 30 score higher than this one. Rarity: 10.2% of birthdays from 1950 to 2009 give 6 and 0.9% give 33, so about 1 in 560 random pairs of birthdays land on exactly this pair.

The rule is our own design, not a numerologist's chart, and numerology is not a science.