If I was advising QF, and the check only takes one hour (if that) then I would advise them to conduct a one off check of all 737-800s, followed by a weekly check of all with > 22k cycles and a monthly check of all with < 22k cycles.
Its cheap to do requiring approximately 1.5x FTE to be allocated, it goes beyond OEM and regulatory requirements, it will give the travelling public reassurance that QF is a safety leader and furthermore, QF can claim world class visibility into the emerging PF cracking issue.
Unless Boeing has isolated the cause to something other than cycle or age related, it's clearly going to be an ongoing issue for some time.