basically in monitor mode the amount of data that you get on the can bus will cause you to loose some data if you monitor all messages on the can bus... This is true on all the low cost scantools OBDPro, ELM etc...
However there are ways around this
All the OBD II data has a set of id's allocated to it so the scantool automatically set's the filters and masks to ensure that only the obd II messages are being recieved.
In monitor mode you can custom set the filters and masks to get a set of data that you are interested in... (This is where the mongoose etc have more bandwidth due to the higher ram availability)The OBDPro double buffers the data so compared to the ELM it will have quite a bitmore head room before issuing the BUFFER OVERFLOW command.
To explain further...
Say you are working with a 11 bit can vehicle and you want to find the door unlock message (just as an example)
You could set the masks to only monitor messages originating from id's 0 to 100, start monitoring hit the door and see if you can spot a pattern, if not change masks to monitor between 100 to 200 and repeat...
Thanks
Paul
www.obdpros.com