[LJR69]

Just having a quick look suggests you are correct. The 800 appears to have a full power recycle time of 4 seconds, while the 900 is 2.2. Interestingly though the 600 has a recycle time of 2.5 and is only very slightly less powerful than the 900, but I guess you get a commander mode flash that auto detects DX/FX sensors with that small performance improvement.