Let me rephrase the method: run a 600m time trial at full-effort in training, with or without training partners - depending upon what works for you, and typically the ratio between the 600m time and a later 800m race time is quite close to 1.40. Maybe Nick needs a pacer ahead of him to eye. Maybe Scherer doesn't. What matter is they gave full effort or very close to it with the premise they were practicing race-like stress and getting ready to soon do an 800m race that mattered to them.
Like sub4 poster, I've never seen a runner have a 1.33 ratio from a 600m time trial to an 800m race IF the time trial was run at or extremely close to 100% effort. As sub4 said, if your instructions are to the runner you're coach is "Run hard but don't kill yourself!" then it's proable the athlete might have ran a second or a second and half faster. It's totally realistic to tell a runner to give a hard but not all-out effort, which means the athlete saves a bit for race-day and actually has a 1.33-1.36 ratio. It's also realistic for athletes to hold back (of their own volition) in a time trial because they want to save a little for race-day.
I don't think the main point I have about using the 1.40 ratio is what sub4 eluded to: it's realistic information for the athlete. It's far more helpful to use 1.40 as a realistic ratio and have the athelte pace accordingly than give them a 1.33 ratio have them go out way too fast. Example below:
Jim time-trials 600m at full effort or within a percent of full effort in 79 seconds flat. The coach tells him he can either use 1.33 or 1.40 as the ratio; yielding predicitons of 1:45.07 and 1:50.6.. If the standard rate of racing is a 3 second difference between the first and second lap for a top 800m runner, due to energetic changes from glycolytic to oxidative phosphorylation - then a time of the first lap for the 1.33 ratio is 51.035 seconds, while the first lap is 53.8 seconds. That's a big, big difference in fatigue at then end of one lap duoe to a 2.765 seconds time difference!
Let's take Seb Coe and have him do a 600m time trial at full effort. He records 1:13.6, which he did during his best racing year. We use the 1.33 factor and that predicts 1:37.888 for 800m. If he used a 3 seconds differential between laps, as is common, then he'd have to cover the first lap in 47.44 seconds (1.5 seconds below the mean time for the predicted 800m time using hte 1.33 ratio). I don't know about you, but 47.4 seems way too fast! Using the 1.40 ratio, predicting 1:43.04 (whichi s a common race-time for Coe for 96% of his best racing seasons), his first lap of an 800m race would be 50.02 seconds, which is about what he normally did during 1:43 races.
I don't mean for my discourse to be agitating or put down anyone personally: I am only sharing my method of predicting 800m times based on 600m time-trials; based on many observed performances from runners who are world-class to average 800m runners in high school. Across the board, I've noted 800m specialist having ratios quite close to 1.40.