Thanks I stumbled across that but I wasn't sure since the following steps are also wrong. For example the non-existent export button. I think these instructions need to be revised a bit. Maybe segment the ZD and SZ sections rather than lumping them together.
The FAQ link that's referenced in the first paragraph includes a statement about ZD's certificate refresh: "ZoneDirector 9.13+ has the ability to report an AP certificate status and refresh AP certificate (for future SZ migration), but does not require certificate check in order for APs to join."