Timed Set Progression Model?

Just tinkering around with some ideas for assistance-type work and was thinking about using a timed set as a form of progression. Does anyone have any experience, thoughts or warnings about something like:

  • Week 1: 4 x 45s
  • Week 2: 4 x 50s
  • Week 3: 4 x 55s
  • Week 4: 4 x 60s
  • Week 5: 4 x 45s etc.