Patience my friend. IME, Jake's statement is accurate. Don't forget, it came out of a high light / high food environment.
Once it gets going, the projections seem to grow weekly if not daily. If one considers the amount of surface area on those projections (compared with a flat surface), the quantity of growth can be remarkable. Not quite M. digitata like, but substantial none the less.
Feeding with Reef Nut. Oyster and / or Roti Feasts should help move it along.