A die-hard Rodinal user would never say 10 ml. I've got a 500 ml bottle in front of me (AgfaPhoto Rodinal) and on the box it says:

"Working capacity: For 30 to 80 rolls of 35 mm films with 36 exposures depending on dilution."

500/80=6,25 ml. Usually they state 7 ml is the official, but 5 ml works just fine.