NO! you are wrong - there are 453 drops. LOL
Seriously, I have found that depending on what you use to put the hole in the end of the nozzle affects the size of the drops. If you buy a container from Bears Baits, it comes with an insert (or it did a year ago) that has quite a large hole and can really make a big drop if you squeeze too hard. The MF one ounce bottles have a similar insert with a much smaller hole. So, it is hard to say how many drops in an ounce because of these variables.
I use the same pin to puncture nozzles, adapt each recipe as I try them to suite my tastes and keep records in a loose leaf binder. Keep in mind that all manufacturers colorants are different and require adjustments when changing from one to another.