Tonking along at 50km/h and top assist will have an affect on cells, demanding high amps constantly.
Which cells did you use ?
Range will be even better probably at least triple in PAS 2 and about double in PAS 3, for longer cell life use the lower PAS and save high PAS for inclines.
On shared paths hopefully you are respectful of other users as you must know you are affectively riding a moped in the guise of a bent.