I am sorry to be a spoilsport, but I believe that any surgeon who uses drainage tubes for "standard" breast augmentation is causing their patients to have a higher risk of infection, capsular contracture, and re-operation. If the pocket is created atraumatically, without blunt dissection, and with precise and complete bleeding control, drains are neither necessary nor desirable!
Sure, if this surgeon's type of breast implant surgical technique causes so much bleeding that a drain is "needed" to evacuate the blood and serum from their patient's breast pockets, a drain may reduce the re-operations for hematoma. But allowing a portal for blood and serum to drain out also can allow bacteria IN, which is an absolute major problem when implants are involved. Bacterial contamination can occur, and biofilms (even from "normal" skin or intraductal bacteria) can stimulate capsular contracture. I have done thousands of breast augmentations for over 24 years without one drain being used or "necessary." Ask an orthopedic surgeon if he or she uses drains in "standard" hip or knee replacements. Too much risk of infecting the hip or knee components! The same goes for breast implants!
240cc drainage per day at 4 days post op is a lot of drainage, and I personally think you are right to be concerned. I truly hope this turns out to be "no problem" after your drains are removed, but I already question the judgment that allowed their use in the first place. If you have problems of any kind, please consult with several ABPS-certified experienced plastic surgeons who do lots of breast surgery before doing anything else! Good luck and best wishes!