OK so I've tried using LDAP queries and Filters and the query has been successful, but it still only imports the one user.
LDAP://server/OU=,OU=,DC=,DC=com filter (sAMAccountType=805306368)
or (&(objectCategory=person)(objectClass=user))
or (sAMAccountName=*)
All three return the same results, but only the account from above imports.