two quick questions:
(a) can you explain steps when you show up for a Test - - - arrive and complete test and THEN go to some interview area with all your files and papers and what happens there

You arrive to do the test and the first step is guidance regarding the test, and the interview process. After that they call you individually and go over your file, i.e., the list of absences and the passport stamps. This was done in the same room where everybody gets tested. After that the CIC officer said she'll let me do the test but I'll be given the RQ.
(b) NEXUS question - - When you mention Nexus and the whole issue that they maybe could not reconcile numbers - - is it that you used Nexus more for land crossings into US versus airline travel ? Since there are always stamps for airline travel YES ?
On the contrary, air travel no longer requires stamps. Land crossing will generate a stamp in passport.