Hi,
Yes, that should trigger the wp_cron actions in wordpress, however I don’t exactly know if there are multiple cron events, how it is distributed, if distributed in any way.
I have checked the cron related source code, but I don’t see any issues there, the only section where the cron jobs are deleted, when the new settings are saved on the index table options – but right after that, the new cron jobs are immediately registered again.
The execution timer can be inaccurate, I would rather check if there are any posts left to be indexed. If the counter stays on 0, or gradually lowers (if many posts are added), then it should be fine.