Western, or Pythagorean, numerology assigns letters values 1 through 9 in strict alphabetical sequence, repeating the cycle. Chaldean numerology, which claims older roots, uses a different letter-value table and treats the number 9 as too sacred to assign to any letter at all.
Vedic numerology, tied to Indian astrological tradition, sometimes calculates a comparable "name number" but weights it differently against birth-based numbers, which it treats as primary.
None of this is a case of one school being more "correct" than another — they're separate rule sets that happen to use the same vocabulary. A destiny number of 7 in one system and a destiny number of 4 in another, calculated from the identical name, aren't a contradiction. They're just different games with different rules.
