Custody backfill sync shows incorrect estimated time to completion

```
Oct 22 15:19:18.006 INFO  Downloading historical data columns  
distance: "640 slots (2 hrs 8 mins)", speed: "51.33 slots/sec", est_time: "2 hrs 8 mins"
```

The estimated time the speedo notifier calculates seems incorrect for Custody backfill sync. In the above log, it seems like the distance (640 slots = 2hrs 8mins) is being used to display the estimated time. 