Planted tanks cycle faster?

I hope you don't mind another newbie kind of question...

My first tank is near the end of its second week of cycling. It is a 90gal
and is about 75% planted. I started with 3 black mollies, 6 platies, 3 otos,
and 1 pleco to cycle the tank. I measured ammonia and nitrite levels
every day, and the ammonia peaked at < .25ppm on the fourth or fifth
day and dropped to zero. Nitrite peaked two days ago at .25ppm, and dropped
to almost zero today. I lost one platy on the third day - not sure
if it was already sick or the ammonia killed it. I found it stuck on the 
Fluval intake in the morning. A week ago, my local store had a 5 for 1.99
sale on zebra danios, and I was curious if adding some more fish would
affect ammonia and nitrite levels, so I added 5 zebra danios to the tank.
I could not detect any significant levels of either ammonia or nitrite a
few days afterwards. Two days ago I added 3 more otos to control increasing
amount of green algae.

I was under the impression that cycling a tank takes a month or more. Is my
tank already cycled? If so, do plants really help to speed up cycling this
much. I also used Hagen's Cycle additive in the beginning but am not sure
if it made any difference or not. I want to add a few expensive crypts ($25
each!) and perhaps a tiger lotus or two. I also want to add a school of
corys and may be two pairs of angelfish.  Can I safely do that now or should
I wait another week or so to be sure? 

 John Y. Ching (jyching at watnow_uwaterloo.ca)    |
 Pattern Analysis and Machine Intelligence Lab	| 
 Department of Systems Design Engineering      	| 
 University of Waterloo, Canada            	|