Hi,
To place points at cursor position, juste press number key :
KEYPAD 0 = position 0%
KEYPAD 1 = position 10%
KEYPAD 2 = position 20%
…
KEYPAD 9 = position 90%
KEYPAD . = position 100%
You can change this in the menu Option → Keys
Also, you don’t edit the file.script directly. Th data is store in the editor, in a project. When you finish the job, you must export the file.script.
The project can be saved, and you can store many script in a projet.
At first it’s a bit tiring but after a time of habituation this tool is really useful and very permissive
You can program some personal tool with the language Lua or use some tool posted be other peaple.
Exemple I create this tool : https://discuss.eroscripts.com/t/my-tools-extension-for-openfunscripter/61434?u=limitlessman
And I will add more stuff soon 
Or this one is realy cool :
https://discuss.eroscripts.com/t/motion-tracking-funscript-generator-v0-3-x/28117?u=limitlessman