Bryan's BC numbers convert to .481 for the .257 VLD and .562 for the .243 VLD, which is actually slightly more in the .243's favour than the factory advertised numbers.
In any case, I agree with you that the differences are essentially moot to 1000. The .243 drifts slightly less, and the .25-06 shoots slightly flatter. But the .243 uses 10gr less powder to achieve that performance
