I have. In a post somewhere on this forum. I called it Concord Response Time, or CRT. All Empire space would simply have a CRT level. Thus 0.5 sec space would be 19 CRT, or CRT 19. No confusion. No need to consult a table.
Low security space could be GGR for Gate Gun Response. I have no idea what the numbers currently mean though or what difference it makes if 0.4 or 0.3 so I can’t come up with any numbers for it.
NCR space could be Null. No Concord Response.
None of that was hard.
Edit: The original ideas I posted as Renly Rohan here: Closed - #111 by Renly_Rohan