(Something else I've noticed over the last 20 years is that RP standard times are very gradually getting close to the old Raceform Standard Times, suggesting to me that Ken Hussey was more accurate all those years ago.)
Those old split second standards are based on record times (I think with an assumed 100 rated horse carrying 9 stone, but I could be wrong abotu that). So RP standards getting shorter will happen over time.
I pulled all the RP standards apart a few years ago (maybe 7 - 8 years ago now). I looked at the time between each distance they had, and converted it to a time per furlong. Lots of them didn't make sense. I recall the 1M4F start at Wolves looking crazy, as despite the turn, the 1m4F horses starting there, were assumed to be clocking furlong times quicker than they were for the 1m1.5F start and their first furlong times.
So yeah, the difference between the standards between each distance (when converted into seconds per furlong), don't look right with a lot fo the RP standards, or at least they didn't and hadn't done for years. The actual distances were checked, as I had measured usign GE before they all got remeasured with shortcuts, thanks to Rowlands and his 1 off the rail average idealism for all CD's, not that it affected me, other than needing to alter spreadsheets.
I may have made that sound over-complicated.
1) Take the 6F STD and subtract the 5F STD, divide by 'actual yards' between the two distances and multiply by 220.
2) Take the 7f STD and subtract the 6F STD, divide by 'actual yards' between the two distances and multiply by 220.
Carry on like this until you've done all the distances at a course. Then you can consider bends and gradients and how the longer the distance the slower the horses. It will highlight where the RP STD's are in error (or any Standard times). Be careful of what now can be shortcuts though (rail huggers).
It's actually a really handy way to locate an error and double check your own srtandards. A crude example would be, you have the 1M standard correct and the 6F standard correct, but for some reason the 7F standard is too easy or too hard, it will show up, as the seconds per furlong at 7F will be either too close to the 6F, or too close to the 1M time. if you look at the number you produce doign this t a course and then look at the course on GE and consider things bends and usign the groudn above sea level in feet display, you can seriously fine tune and remove any errors from your (or any) standard times.
I made a spreadsheet for ease of use, but that'll be on an old laptop, and unsure if it will even fire up now. It's not hard to do it just using a calculator though.