PLT RPTS A DISCREPANCY BETWEEN AIM GPS TAA INSTRUCTIONS AND DESCRIPTIONS: MAINTAIN ALT VERSUS MINIMUM ALT.

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I'M CURRENTLY INVOLVED IN A FLYING CLUB THAT IS TEACHING MEMBERS HOW TO USE RECENTLY INSTALLED IFR GPS EQUIPMENT. IN REVIEWING THE GPS TAA APCH; MOST PLTS HAD MANY QUESTIONS AND WERE CONFUSED BY THE LACK OF DEFINITION AND CONSISTENCY WHEN COMPARING WHAT THE AIM SAYS IN SECTION 5-4-5; WHAT THE AIM FIGURES SHOW; AND WHAT IS ACTUALLY ON A GPS TAA APCH PLATE. THE WORDING IN THE AIM STATES THAT THE PLT IS TO COMPLETE THE APCH 'AT THE ALT DEPICTED' ON THE APCH PLATE. THIS SOUNDS LIKE A MANDATORY ALT BUT THE AIM DIAGRAMS SHOW THE ALT AS UNDERLINED -- MEANING AT PLT'S DISCRETION ALT. THIS IS FURTHER CONFUSED BY LOOKING AT AN ACTUAL GPS TAA APCH PLATE. HERE THE ALTS ARE SHOWN IN BOXES AND LOOK LIKE MSA'S ON OTHER APCH PROCS. THE END RESULT IS -- MOST PLTS IN OUR GROUP DO NOT HAVE A CLR UNDERSTANDING OF THE PROCS AND REQUIREMENTS FOR A GPS TAA APCH. THIS IS A SERIOUS; POTENTIAL SAFETY ISSUE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR POINTED OUT THE CONTRADICTIONS. THERE IS A GOOD DEAL OF CONFUSION ABOUT THESE SEEMINGLY MINOR ISSUES AT HIS FLYING CLUB. THE RPTR HAS BEEN TO HIS LOCAL FSDO AND ATC PROCS PEOPLE AND HAS ONLY BEEN ABLE TO OBTAIN OPINIONS ABOUT THE MEANING OF WHAT HE SEES AS CONTRADICTIONS. SO HE FEELS HE HAS NO RESOLUTION TO HIS MISGIVINGS. HE IS THE LOCAL FLYING CLUB'S SAFETY REPRESENTATIVE TO THE FAA.