eg
Time place Time Place Diff
13:01 psc 14.01 midd 1:00
15:23 psc 16:24 midd 1:01
17:42 midd 19:23 psc 2:19
=total hrs-mins
x by 12 = miles

Need to calc the between 13:01 & 14:01 then the diff in time next entry
Then give Add the two time diffs X by 12 to give me miles