He can respect Vox for at least attempting to haggle with him, most are too intimidated by the time a Deal is ready to be struck. But he still cannot agree to that changed wording, mostly because he has no control over what the Vees do themselves and how their actions might get them onto Lucifer's radar.

"Should the Vees appear on Lucifer's radar, I will use what influence I have to ensure any retaliation is non-lethal, and in return you will assist with the Hotel under my leadership for as long as I am helping with it."

Vox doesn't need to know that Alastor's influence with Lucifer is literally less than zero, and in fact if he said not to hurt the Vees then the King might annihilate them just to annoy Alastor.