I apologize that I completely blanked on your question. YES, you can use Exbal, at least on the PPC, to adjust for distance to chrono. It just take a bit of effort in a roundabout way and the program will cuss you out in the process.
This is how I do it and I'm not sure how scientific it is, so perhaps someone can set me straight.
When you hit 'calculate', it only lets you do so if the yardage entered is 25 or more, right?
Well, one thing you can do is put your chrono at 25 yards (which I do when shooting prone often becuase it has to be out that far and downslope so that I can actually shoot through the screens), but that's NOT what this post is about.
When you hit 'calculate', you can enter a number smaller than 25 (i.e. the yardage to you chrono (let's say 12 yards to chrono) after estimating your MV given what your chrono says) and hit 'recalculate'. A screen pops up that says something along the line like 'you're a dummy and you can't do that'. I just hit OK (admitting I'm a dummy...) and then hit 'recalculate' a second time and it will (does on mine anyway through two diff. versions of exbal) calculate for the 12 yard data if your chrono happens to be at 12 yards, including the giving you the velocity at 12 yards. Keep adjusting MV under 'bullet data' and go back to the 'calculate' button for 12 yards using the above sequence until the 12 yard (or whatever distance your chrono is from your muzzle) velocity matches what your chrono says, then I know, or think I know my true MV.
This may not be as accurate as JBM, I don't know, and haven't compared, but it sure seems like it's got to be awfully close and certainly work in a pinch in the field if need be.
Anyway, sorry for completely blanking on this on my earlier post. I do this all the time when I'm working with Exbal when practicing in the field over the chrono to figure my true MV and am not sure why I forgot to mention it. Did it today at 15 yards working with my brother and his rifle...(not long after we'd spotted 30 Mountain Goats while bear hunting early this morning...no bears, of course.)
Hope this helps,