at my parent. Out to 1 mile trail, around 4 times, and back. The watch cal was set to 1.000 after the battery replacement. It gave 7.75 total and 3.85 for the 4 laps (this track really is a mile). The new cal factor should have been 1.040 (4/3.85), but I screwed up when trying to calculcate it based on the watch and messed up compensating for the watches incorrect miles to km conversion. Anyway I changed the cal factor to 1.055.
We'll call this run 7.75*4/3.85 = 8.05.