Assuming it'd be too hard to change the level progression, here's a way to tweak the rank progression to be somewhat more reasonable:
- 1: Cadet
- 3: Ensign
- 10: Lieutenant J.G.
- 20: Lieutenant
- 30: Lieutenant Commander
- 40: Commander
- 45: Captain
- 50: Commodore / Rear Admiral, Lower Half
- 55: Rear Admiral / Rear Admiral, Upper Half
- 60: Vice Admiral
- 65: Admiral
- 70: Fleet Admiral
If the level progression can change too, here's what I'd do:
- 1: Cadet
- 10: Ensign
- 20: Lieutenant J.G.
- 30: Lieutenant
- 40: Lieutenant Commander
- 50: Commander
- 60: Captain
- 70: Commodore / Rear Admiral, Lower Half
- 80: Rear Admiral / Rear Admiral, Upper Half
- 90: Vice Admiral
- 100: Admiral
- 110: Fleet Admiral