I would suggest he has been misinformed or is making a guess. While his explanation might seem reasonable, it ignores the basic principle of inaccurate GPS altitude generation. It also ignores the fact that GPS is never really turned off. It continues to function normally. Turning it off is simply an instruction to the Flight Controller to disregard GPS for station keeping. The calculations for distance continue to be displayed. Whether it is on or off doesn't matter because it isn't used for altitude.his response was in angle mode the barometer and GPS is used to verify altitude ,in manual mode obviously the barometer is used so ,take it for what it’s worth.
This would not be the first time a tech had the wrong information. I has happened many times and in some cases a tech will give horrendous advice to a caller. I suspect the training they get is meager. Again, I'm not critical of you. I simply have an aversion to incorrect technical information. It may seem like a trivial matter but it sets in motion more speculation which is also incorrect. Consider this: "I need a new GPS board because my altitude reading is wrong." "My H crashed into the ground because my GPS altitude forced it into a dive."