With you here.
And I like knowing that my gear and speakers can be at a measured "zero" starting point, then I can adjust from there (sort of like doing a recipe the way it is written the first time and after trying it, adjusting it to your preferences).
At that point I can measure again & then, knowing what the end measurements are, after I have adjusted from flat, I can duplicate that measurement from the on (or until I want to change things up). But if something messes up or I have to insert a new piece of gear, I can take it the system back to zero & then easily adjust it to my preferences.
Not having a "Zero": point to start from, makes it more difficult.
So I definitely want that "zero" point to start off with.