I think your conclusion is wrong.
Looking at the 1st stint average times, it would appear that Hartley is faster on average than the Saubers and Williams, and relatively close to Force India.
However, this does not account for the following factors:
- Hartley stopped after lap 1 for brand new Soft tyres.
- Hartley was running in clean air for his first stint, while everybody else was in a bunched up fight, likely to be losing downforce, increasing tyre wear.
- Hartley's stint length was shorter than everyone, bar Leclerc.
- Sirotkin, Ericsson and Gasly don't have realistic representation considering they stopped running in the first stint.
In stint 2 Hartley is slower than everybody else by close to 1 second a lap or more, on average, other than Stroll. His closest competitors have all retired by that point. In addition, Hartley's degradation per lap was higher than every other driver, other than Ocon.
More worryingly, compare Hartley's degradation on the Ultra in stint 2 to Alonso's or Vandoorne's degradation on the Ultra in stint 1.
Hartley - 0.183 seconds per lap over 30 laps.
Alonso - 0.129 seconds per lap over 24 laps.
Van Doorne - 0.103 seconds per lap over 23 laps.
Even Vettel who had used Ultras in stint 1 experienced degradation of 0.097 seconds per lap across 24 laps, approximately half that of Hartley.
The Toro Rosso's degradation was about 50% higher on Ultras than most other cars, and in circumstances I would have considered more favourable, given Hartley was running with less additional weight in the car having burned off fuel.
At best I think you can conclude Hartley's pace was similar to Strolls. There is no evidence he was categorically faster than the Williams. In addition, you can't conclude anything relative to Sauber, as both Sauber's stopped running. Leclerc's times suggest Sauber also eat their tyres, but they had similar race pace to Toro Rosso.
There is no way in hell the Toro Rosso is
near the Force India's pace, unless you consider 'near' to mean 30-40 seconds slower over a race distance.