The skill Born Leader has no effect on Accuracy During Rotation (ADR) 0%. Born Leader improves Accuracy During Movement (ADM) by 4%. I tested this with a one-skill commander.
The Skill Steady Aim improves ADR by 20% (too much) and improves ADM by 10% (the correct amount) Again a 1-skill commander.
When combining the two skills:
ADR is improved 21% which is only a 1% improvement over just Steady aim but still it is too much for the combination.
ADM is 14.5% better which is 4.5% better than just Steady Aim and likely the correct amount.
I used a 2-skill commander.
So Born Leader, on its own, does nothing for Accuracy During Rotation. But Steady Aim does too much for ADR. 20% which is double what it should do. The combination of Born Leader and Steady Aim improve ADR by about 6.5% too much. 21% vs 14.5%