I don't use a drop weight, as I have a decent electronic machine, but the time to string is the time spent on the racquet to service it, is it not?
My time would be:
The time to check the integrity of the racquet for fractures/ cracks, and inspect the grommets(very important, as a slight crack unnoticed in the frame can turn into a new racquet for the client, I have spotted this before stringing to avoid issues)
time to cut out the strings properly, and recheck the grommets again.
time to replace any broken/cracked grommet if present.
time to mount the racquet properly on the machine.
time to measure/cut string,
if nat. gut, time to manually prestretch the string.
time to look up pattern if unfamiliar pattern.
time to string the racquet.
time to straighten main strings primarily.
time to write label, and mark down racquet serial # in log book. (Very important,to keep records but thats another topic).
time to place an overgrip if the grip is in poor shape, and I usually don't even charge for that, as well as the time.
All this is time spent on customers racquet as well as time talking to him on his game and string and tension choices before you even start, and it all adds up.
The thread is about time to string on a drop-weight, but you solidified my point. Although I am not a pro stringer, you mention several steps that I forgot, that even home stringers need to include in their stringing time. For example, I have had to look up stringing patterns several times on friend's racquets that I have strung.