I haven't seen Sam, and I've only heard the ship's computer. That could be Sam using the ship's intercom system.
Computer, if I were to give you fifty credits and ask for change, what would you give me back? Change must contain a twenty, tens, fives, and ones.
Twenty, two tens, five, five ones. Twenty, ten, three fives, five ones. Twenty, ten, two fives, ten ones. Twenty, ten, five, fifteen ones.
That's not Sam. In each case, the change actually adds up to fifty.