Administration is International ISAF committee with Representation by national members. I represent the USA.... Happy to hand this over to an engineer who could contribute a bit more then I can!!!
(but you know that)

Your premise that there is an accurate rating table is a unicorn…. Find one system, used in the world that sailors agree is “accurate”
I have done Jakes calculation comparing time deltas for each and every update of the ratings….. It’s a matter of opinion what is accurate… as Todd replies to Dave…. Looks like the ratios are the same…. So…. You can argue this … till you die.

So, you won’t find an accurate ratings table under a rock or patch of weed…
What you will find is a group of owners who forge a consensus… that XXX sucks but it sucks less then all other attempts in the past…. AND we are willing to pay XXX for its administration.
The group of owners then go out and get Official Sanction for their rating system… Big boats now favor HPR…. And pay 500 to 1000 to get their boats measured while the last great hope… IRC (pay about 100) has collapsed in the US.

So... the last time we made a change... from NAMSA to US SAILING... There were no compelling issues driving a switch…(as their is currently) Rather… US Sailing, with Darline at the helm decided to work extra hard at getting beach cat ratings updated in the US Sailing run successor to the Dixie Portsmouth system. There was no “The Man” telling clubs and sailors what to do…
So… monohull sailors saw the regionally run system now administered by US Sailing (and the Dixie label was dropped…. )had value as a national system run by the National sailing body and supported it. US Sailing Sanction mattered for widespread acceptance…. Likewise, Catsailors, decided that national sanction was important and cat clubs around the country voted to run their events under US Sailing Portsmouth.
The current UPSET is that US Portsmouth won’t do its job of nationally sanctioning a rating (bogus or not)… So… national sanction matters to race organizers…. Because it does.
So… in the US…. What could you do…
Step One, get the active one design classes to vote on their preferred handicap system.
A dated Portsmouth system that creates ratings for all recent designs using PHRF principles to stay current Or a measurement system administered by ISAF via the SCHRS committee.
Step Two, get Organizing authorities who run handicap races to make their preference clear in their NOR… (Sailors ask for and get what they want)
Step Three, Ask US Sailing to make the recommendation that beach cats use SCHRS for racing and Portsmouth/PHRF for mixed fleet (lasers et al) racing.
Its about getting a consensus and authority sanction for a system with transparancy and pretty good accuracy
.
At the national level, It starts with the OD classes who represent their sailors and do their part to LEAD. At the local level, some clubs have already jumped from Portsmouth/PHRF to SCHRS

SCHRS is transparent... the rating formula is published and applied to all cat classes to get a rating. NO PHRF principals/ vodoo opinion applied. No need for large amounts of QUALIFIED race data to get ratings.

Yes… its spring time again.!