Those getting 3.5 probably did not get a pay raise since NQ (or they may have a commission component in their remuneration).

Smaller firms may start at 3.5/3.8/4.0 at NQ level and give a 300 to 500 raise every year. There are also mid-sized firms with similar basic pay but supplement it with a frontload bonus to bump up the monthly pay to 4.8 to 5.5 for a 2 PQE.