Blimey, that's clever. How does your planning department know whether SLOP will be needed, and where all the other aircarft are going to be, or have I got the wrong end of the stick here?
I just look at the traffic around me on TCAS and SLOP into the 'lane' with least traffic, or to get out of someone's wake.
SLOP of course was brought in because with modern navigation systems, all aircraft in an airway are nowadays EXACTLY above/below each other, whereas in the past, errors in old Nav kit meant that there was always a spread of positions within the airway, which tended to distribute the aircraft around.