I'll try and answer the details to the best of my knowledge but will request other experts on this forum to also chime in.
So here how it goes.
Email content prepared on marketing instance.
Delivery submitted for content approval.
Delivery target prepared at the end of Step 2.
Delivery submitted for target approval.
Target approval granted by the reviewer.
At this point, the delivery parts and then sent over from Marketing to MID. At this point, you will start to see the broadLogMid schema on MID side getting populated with delivery logs.
Marketer hits Confirm delivery on marketing.
API call to MID puts the delivery on MID In motion.
Real time updates of broadLogs take place on MID as soon as the MTA childs send out emails to target MX server.
Marketing instance has mid sourcing workflows running at 1 hour and another one running every 15 minutes. So delivery counters are updated every 15 minutes by default but the logs are fetched and updated every one hour.
These mid sourcing workflows are there to update delviery logs and the delivery counters.
Tracking workflow is responsible for updating tracking information.
If you are observing delay in updates of delivery logs and that delay coincides with execution of mid sourcing workflow then things are working as designed,
You can modify the scheduler run time but ensure that the window is not too small.
If the tracking logs are getting updated with a delay, try and analyzie what is causing this issue. Trackign workflow pulls information from tracking server which in your case can be same as mid sourcing server.