Sirius,
What I'm trying to point out (hopefully in a good-natured and humorous fashion) is that drops are really accurate, as accurate as measuring with the graduated cylinder, especially for smaller amounts where measuring error with the graduated cylinder is much larger. One method is no better than the other. Both are "right" and will not result in stained negatives.
If one uses an eyedropper or the like and lets drops slowly form and fall under their own weight, each drop is, within a very small margin, the same volume. The margin of error measuring a ml or so in a graduated cylinder is likely much higher unless one uses a thin graduated pipette or syringe (which I do for developer stock solutions where I need 5ml or more). I find it more convenient at the Photo-Flo stage to simply measure out the requisite number of drops with an eyedropper. I'm confident that my measurement accuracy is well-within the margin of error for mixing that particular solution. Point being: I'm not being slapdash or sloppy here.
Here in Europe, many very strongly-concentrated medications are sold to consumers in bottles with a drop-dispenser top. Doses are given in number of drops. Some of these medicines contain opiods, etc., which need rather careful dosing. The drop method, again, does the job within the margin of error for that particular application.
My point is simply that drops are accurate and could present a more convenient method of measuring out Photo-Flo or small amounts of other concentrated stock solutions than using a graduated cylinder for many. I use drops for mixing bleaches, wetting agents, developer additives and small amounts of other aqueous stock solutions. I use syringes for volumes from 5-10ml or so. I have a battery of different graduated cylinders in sizes from 15ml to 2 liters. I use what I feel is most accurate and appropriate for the task at hand.
Best,
Doremus