@sudolea Yes you observed it correctly. But is is not a big issue. The route will be new calculated at booths devices and small differences are normal. The computing engines at the devices are different and therefore the results as well. Maybe some guys from the developers team can comment this behaviors.
I can see similar time differences with BaseCamp routes at my ZumoXT.
Appendix. When I press the start button at both devices the results (distance and time) are the same.