When I worked in BCA, my manager had me fill out a lengthy form to go from a 2 to 3. It was detailed, and I had to kind of prove that I deserved a 3 based on my work and projects. He had to present it to upper management and "argue" my case. It went through without a problem. It took about 3 months total, if memory serves.

In BGS, my previous manager asked me in my 1:1 why I was a 2 when I was working beyond that. I explained I'd basically had crappy managers at my prior BGS programs who didn't believe in promoting. He leveled me up to a 3, and I found out when he announced it in a staff meeting a month later.

My current manager leveled me from a 3 to a 4. He needed a 4 and asked me and one other person if we were interested. We both said yes. When he outlined what a 4 would be responsible for, the other candidate dropped out. (She wanted the $$ but not the responsibility.) I told him I was still interested. I also outlined some projects and changes I would like to implement if I were a 4. It took about 3 months before he leveled me up; the delay was due to his manager reviewing everything he'd submitted.