Based on what I've seen across multiple companies, only the biggest and most experienced ones understood how to do leveling correctly. Everyone else was basically flying by the seat of their pants.
I think it's much more productive to label software engineers as being in stage 1 through stage 4 for most companies, and for 1000+ add stage 5 and for 10000+ add stage 6.
There was also a stretch of time following the dotcom bust when companies were handing out inflated titles rather than actual promotions or pay increases. I could be misremembering, but my memory is that was when titles became meaningless.