The 67 dB rule applies to ISO/IEC Channel test limits containing the PS ACR-F measurement.
If at any frequency the PS FEXT is less than 67 dB, the PS ACR-F cannot fail at that frequency.
PS ACR-F is a calculation of PS FEXT minus the Insertion Loss.
On VERY RARE occasions, you may see "i" against the PS ACR-F summary result, meaning that the entire PS FEXT measurement was less than 67 dB for all pair combinations, so all of the PS ACR-F calculations are "ignored" or as the standards phrase it; "for information only".
This "i" will ressult in N/A appearing in the LinkWare Software and is nothing to be concerned about.
This was added in Version 2.74 Software.
Practically speaking, it will not turn an existing FAIL into a PASS or vice versa.