Arlene - "If" I understand this correctly - since you used ISO 100 instead of ASA 25 (note ASA = ISO American Standards Association vs. International Standards Organization), that means that your values should be FOUR TIMES the values given in the example listed before your values. A value of 4000 with your camera set as you listed it is actually only 1000. Anyone - chime in and correct me if I'm not seeing this correctly. If this be correct, we are now coming into some realm of commonality in values.
Here is another link on plant lighting that I have found particularly interesting and useful.
http://retirees.uwaterloo.ca/~jerry/orchids/light.html