Hello DrB,

So is it more correct to leave the parameter on when having direction sets?

As already mentioned, it depends on your data. In set of directions (not direction angles), the orientation can be arbitrary and must be estimated with the adjustment procedure.

If it always has to aproximate an orientation angle, why does it influence it in the adjustment results so much?

I'm not sure what you're referring to. The orientation is just an auxiliary parameter.

Best regards
Micha