The sequence of this cycling indication on the control panel (base skin) is:
(1) current time / total time
in hours:minutes:seconds (optionally milliseconds) (2) current time
(=time past) (3) remaining time
(4) current frame number (1) current time /total time
(2) ... etc.
This feature has been there since the early days of BS.Player.
E.g. I just checked in version 0.86.501 of 2005.
(Most recent version now being 2.56.1043.)