not necessarily.. You could verify solutions at the range but most people will use the software in the field for hunting or "tactical" scenarios..
One you have made range cards for different atmospheric conditions at your local range there isn't much need for a calculator. All the terrain variables would always be the same.
Most serious long range hunters and snipers use some type of long range shooting software in the field. (ExBal, WinBallistics, Dexadine, Infinity, etc..) This software is normally downloaded into a PDA and all the current physical and atmospheric variables are entered into the software. (caliber, sight adjustment increments, ballistic coefficient, muzzle velocity, zero distance, zero height, bullet weight, altitude, pressure, temperature, humidity, wind speed, wind direction, slope angle, distance, etc..) The software calculates your shooting solution giving you the correct sight adjustments to hit your target at any given distance, angle, temp, etc..
You start with baseline numbers that are pre-entered into the program. Mostly this is your rifle's load/caliber info. Next you use a portable weather station such as a Kestrel to obtain and input the atmospheric conditions. Then you use a cosine indicator to get the angle up/down hill and enter that info into the program. Finally you get your adjustments from the program, adjust your scope and fire.