<blockquote>Frigilux: Update: Just bopped over to CR and noticed that, suddenly, Tide Ultra Stain Release (liquid) gained several points (it now tops the list with a score of 88), while Persil ProClean 2 In 1, which was tied with the Tide product, lost a few points (composite score of 80)--notably in the removal of grass stains.</blockquote> Hmm. I had serious grass (clover) stains on a shirt and jeans from yesterday's mowing.
This is not a scientifically-controlled test so take it accordingly ...
Washed in the F&P (with a pair of socks that didn't have grass stains - wore boots), warm water with Biz powder (4 tbsp + 1.5 tbsp STPP), lowest water level (manual selected), light soil but with a 2-hr soak (includes 5 agitation strokes every minute for the duration). Better but stains still quite visible.
Washed again, with a large bath towel and wash cloth added and not the socks ... warm water, 2nd water level (auto-sensed), light soil + 2-hr soak ... 6 tbsp Biz + 1 tbsp STPP -- and brushed the stained areas with Persil ProClean 2 in 1. Grass stains 100% gone.