I tend to agree for more accuracy, but ya know.... (pregnant pause for the secret)....
listed right there is the currrnet alt, and drop altitude that you calibrated at.
If those match you can bet you're within 4 mph of calibrate alt and it works, I've veered off speed/alt from calibration and went back to match it for drop and hit as usual on drop.
Salvo 2, delay .05 of course, gas dead, gas dead, ammo dead