sha2 module and 2.4.39, iterations question

Hi - openldap version = 2.4.39

With: moduleload pw-sha2.la

I have an application that generates SHA256 b64 encoded hashes w/ a 4byte (16bit) salt and stores them in userPassword and binds work fine

When I add this to slapd.conf:

password-crypt-salt-format $5$rounds=1000$%.16s

And change my application to add 1000 iterations when it writes to userPassword, then binds fail

pw in userPassword is generated in this format: {SSHA256}b64Encoded(sha256Digest1000Iterations(pw+salt)+salt)

Is "password-crypt-salt-format" the correct place to specify we want to use iterations on our hashes? Is this configurable?