Hi.
I've been asking this same question now for a week or two but no responses. This being said: I've done a bit of my own research. Do bear in mind I'm simply surmising here (but nevertheless based on some other posts on other forums I've seen):
It COULD be that the APP tests STREAMING protocols (which differ from HTTP or WEB based protocols). This would explain why a device used for streaming (DStv Explora as good example) reports the same slow speeds at the same time as the APP while download speeds on a PC remain at full speed during the same time (this is my experience anyway). I must admit that I'm surprised that nobody from My Broadband has posted a technical explanation as to why the APP speeds differ from the WEB based test at times (note that it's only when connections are being shaped / throttled that the APP differs from the WEB based speed test).
It COULD be that these service providers simply ensure that most all of the speed tests are not "subjected" to their shaping / throttling. Remember that each of the speed test servers will have an IP address (or range of IP addresses) that is (that are) unique and that are KNOWN to the service providers and it's not that much of a stretch to wonder if they simply allow traffic to these speed test sites to not be shaped / throttled (effectively bypassed) when you run the test thus giving you a false reading (the words "fraudulent reading" come to mind). Afrihost has used this argument i.e. do a speed test and let us know the results. Do an online WEB based speed test and no problem. But do a speed test using the APP (or DStv Explora) and big problem. Today is the first time I've gotten them to put in writing that speeds are slower during peak times but their explanation is a joke i.e. they will still not admit to shaping / throttling (but watch this space)!!!
As to why OOKLA's WEB based speed test AND OOKLA's APP based speed test ALWAYS report the same speeds and they're ALWAYS the faster speeds no matter what time of day: I know not (but this does seem to give some credence to either, or both, of the above).
Not sure if I'm right (technically) above but that's all I can add at the moment. Hope it helps (and maybe we'll get an expert on here to explain and see if I'm right or not).
Regards,
Dale.