Thanks for the detailed response Robert! These are indeed very helpful!
Jerome,
> My questions are:
> 1. Why is the measurement "ongoing" even if the results have already 
> been made available?
One-off measurements are automatically marked "stopped" after 15 minutes 
by the system. This is mostly a book-keeping exercise to know what is 
active and what is not; it does not affect the flow of results.
> 2. What is the meaning of the "requested start time" and "requested stop 
> time" on the RIPE Atlas portal?
The intention is to be able to pre-schedule a meeting into the future 
(for whatever reason you may have) instead of starting it asap, or to 
pre-determine its end if you already know when that should be. I believe 
the "start in future" is applicable to one-offs as well, stop time not 
so much (see above, they are auto-stopped).
> 3. Will a one-off measurement release one slot from the measurement rate 
> limit once its result becomes available even if it’s still in "ongoing" 
> state?
No, the measurement status is what counts. So such a slot is freed up 
after the msm is marked as stopped. We are considering a different 
book-keeping mechanism where the amount of results (activity) is used 
for quotas instead of number of measurements -- but this is not the case 
yet.
We can adjust these limits, so if you have good reasons to do more (e.g. 
measurement campaign, bursts because of some research, etc.) then just 
let us know and we can help!
Regards,
Robert
> Thanks!
> Best,
> Jerome
>