With all four methods??
The ones involving the piano roll also involve selecting all notes first. The ones in the inspector do not. But the ones in the inspectors just add the velocities "afterwards", so in the editors the values do not visually change, you have to listen for it. But with the piano roll methods, they do also change visually.
However, if amongst your selected notes there are already notes of velocity 127, they will not change, and the rest will also "stick", they hit a ceiling. With the cmd-ctrl method, you have to also press the option key while already dragging to avoid this "ceiling". Same goes for downwards change: as soon as one of the notes reaches 1, the rest will not go down either, and you have to add the option key to overrule that.
Another way to avoid this is to simply deselect notes that are already at 127 or 1. This means that the highest velocity note will determine the ceiling, so if the highest note is at 120 for example, you can only drag all notes up 7 values (unless of course you use the option key as described).
If you do the added option key, the disadvantage is that you are losing the relative velocities of the notes, so you will effectively alter the dynamics.