The All Blacks lacked accuracy, especially on attack, in their loss to Ireland at the weekend and have scored just one try in their last two Tests in the northern hemisphere.
Speaking in Rome ahead of this weekend's game against Italy, Foster says coaches are always a bit impatient when trying to implement change.
"We've been round long enough to know that some of the things you've just got to keep chipping away at and overall when you look through the flow of the year, we've actually been pretty happy with where we've got to."
