Gareth
Yes, I would trust RP standard times - in any situation where there have been enough top class races over any particular c/d to firmly establish them.
I wouldn't trust their standard times at Longchamp for a second, nor their calculated going allowance on Sunday.
Normally an 8-race card would be a boon for calculating speed ratings, but as they appear to have completely given up with races over 7f and 8f, they're left with just 5.
Of those 5, the 12f handicap was run over a heavily dolled-out course making comparisons between it and the main races impossible, whilst the Abbaye is run on a completely different strip of ground altogether (although that doesn't stop them including them anyway).
So they're down to just three races. On their system, the Cadran works out as 78lbs slower than the Arc, so that's rendered useless and they're down to two. The Opera works out as 24lbs slower, which if it was considered truly run would put the Arc winner's speed rating in the 140s. So that's out too.
All they've got to go on is the Arc itself. They have no choice but to assume that it was truly run, that the winner ran up to somewhere around their RPR, and then pin the rest of the speed ratings across the card from there. And the going allowance is calculated accordingly. From a single race. That going allowance is then compared against their (fairly arbitrary) table of going descriptions and corresponding allowance ranges, and Soft appears.
Not exactly rigorous, is it?