I understand the concept of soft grades, but, when it gets to the point where the grades are so soft that a v5 is actually a v3, shouldn't they just give it a v3-v4 grade instead of just calling it a soft v5?

All of the boulders in my gym are actually around 2 grades below their given grade, I don't understand why they give them the higher grades and not the actual lower grades. Is there a reason for it?