I know every company will say this, but every single one I've run across has someone who can sign off on something and change it.
"Everyone starts with 2 weeks of PTO per year." -- I've started with 3 or 4, amazingly -- actually entered into the systems, not an informal agreement to allow me to take it. I've found PTO to be the easiest thing to negotiate at the end of the hiring process for a senior+ position.
"Band 6 has a maximum salary of xxxx" -- I've been hired above that.
And these are big companies with formal rules. They all have formal rules for breaking their formal rules, and the person telling you it's a firm rule knows it.
All of this lends itself to new hires getting paid more, of course.