By the way:
Soeaking of altitude and VSI information on iFly iPad .......
Altitude in general is less accurate than horizonyal position on GPS. And in my experience the iPad version is significantly less accurate than the dedicated iFly's are. Perhaps due to the iPad's GPS being not WAAS enabled.
I have had the ipad iFly sometime show obviously grossly inaccurate VSI readings ...such as climb or descent of 3000 feet per minute in my LSA 😏 .
Alex