M code parameters sanity check

[deckingman]

I'm 99.9% sure of this but have a 0.1% doubt. When entering a command but only referencing some parameters, I assume that those parameters which are not referenced will retain their values. For example, I want to reduce the motor currents when homing, for damage limitation in the unlikely even that an end stop switch fails. So at the start of the homing file I have M906 X400 Y400 Z1200. Then at the end I have M906 X1800 Y1800 Z1800. I just want to conform that the E motor currents and the Idle current as set in config.g will be unaffected by doing this.

[dc42]

Missing parameters are given default values, and these are always the existing values where that makes sense.