No. I'm sorry, I think I'm not using the right words.
I started the 1000km of Suzuka the day my Life page told me my loginbonus was 200% when I loaded up the game.
I suspended the race that same day.
Continued the following day and suspended the race again later that day.
The day after that, I finished the race and got my reward calculated @ 200% of which I am absolutely sure.
When I got back to the Life page (finish race, back, back, back from the a-spec pages) I got the welcome message (paint and museum cards) and it told me that my loginbonus was - if memory serves me right - 170%, which I would interpret as 1 day not logging in, which would be the day I resumed but not finished the race.
So, long story short:
Finishing an endurance race, no matter how long it takes, will reward you at the bonus when you started the race.
After the race and reward your bonus will be recalculated where the "resume"-days will count as not-logged-in days and will be deducted from your bonus; just as if you didn't touch the game for those days.
Hope this makes more sense.
And do feel free to correct me where I'm wrong, but that's how I experienced it.