I've been teaching instruments a lot lately. When flying an LPV, LNAV/VNAV, or ILS approach, you start on down at glideslope intercept - GS intercept is by definition the FAF for the approach, whether or not you have reached (or passed) the charted FAF. Due to altimeter errors caused by non-standard temperatures, the actual point of intercept can vary widely from the charted FAF. Especially during the summer, glideslope intercept can occur 1/4 to 1/2 mile before the charted FAF (in the winter, of course, it would be past the FAF). No problem, on an ILS/LPV/LNAV-VNAV, you start down at glideslope intercept and follow glideslope. But then we've got those oddballs, the LNAV+V and LP+V, where Jeppesen/Garmin publish an advisory glideslope that is not evaluated by the FAA. Since these are still non-vertically-guided approaches, the FAF is still where we are to start descending, just like a VOR or LOC-only approach (or LNAV without the +V). However, in warm weather, inbound to the FAF, you will first pass through advisory-glideslope intercept, but can't start descending yet. Then you reach the FAF and can start descending, however the advisory glideslope is now below you. You have basically two choices - do you intercept it from above (which we usually specifically teach not to do with glideslopes), or ignore it? For CFIs - how do you teach how to use the advisory glideslope on "+V" approaches?