Finding some weird features (rules)

[M@LIK]

take the rules i42@2 and @2. They should be identical but they're not. When I test them separately against the phpbb hashes, i42@2 gives me 7520 hits but @2 gives me only 264.

i believe i42@2 would add 2 in the 4th position and delete it:: like
password2 >w/ i42@2> pass2word2 >then> password
@2 would::
password2 >w/ @2> password
directly..
same with $1@1u - u

i really cant find any difference between them.. can u explain with examples plz?? : )