Why no "reverse engineering" ballistics calculators?

[EXPRESS]

I use Ballistic FTE on my iPhone with varied results. It seems to know some bullets, the more commonly used ones better, probably because they have better data for them. For example it works great with the 168gn SMK but not so with the 220gn.

I always shoot and record my data regardless of what the program tells me and find that sometimes I can't get the program to match the reality.
It might match up with the first, or last part of the trajectory, so I tweak the data like BC or MV pr altitude to try to make it fit, but this almost never works.

What I can't understand is; If you can provide MV, and the drop between several distances, why can't they add a function into the software that reverse engineers your data to give you actual BC and fill in the gaps in your data, then predict what the bullet should do at the ranges beyond yours?

[bigngreen]

Exbal is close with trajectory validation, you provide a BC and shoot some drops and put in the amount you adjusted and the amount the POI was off and it tweaks the velocity to match, you can also use multiple BC's to line it up as well but it is not a automatic function.

Loadbase 3.0 has a BC and drag finding utility of sorts that helps you find the exact BC and drag out of your rifle for any given bullet but requires shooting though a crony at range but will yield exact numbers, but few will brave it except Phorwath.

A lot of cold bore shooting in varied conditions with good record keeping will help you know when you need to add a little sauce to the correction that your program is giving you, there are things that they just can not take into account for you.