I appreciate that. I was just adding my 2 cents on the limitations of those apps.
I still think that reading music with bass in hand will do the trick.
Not getting on anybodies case but sight reading as in reading any form of music is one task, playing is another, so by sight reading away from the instrument you reinforce that part not to get in the way of playing, or visa versa. It is a simple premise of learning that it is easier to learn certain elements to internalise them then being them together to be polished off so to speak as one.
As the apps thing will show, you have to learn what keys or buttons to push to get the correct answer, you may know the answer but pushed the wrong button, so it is not that you do not know the answer, its you just accessed the wrong buttons.
Student of mine brought one in for sight reading, he has to read off the notes against the clock, so now the pressure of time is involved and he now has a score to beat...all these things add to him getting the wrong answer, and as he all ready knows the answer when he sees it the app is testing him in a different way.
He was not getting faster times by reading the notes, he was getting better at all the features of the task by recognising what to push without looking for it and forgetting about the clock, the clock means nothing to the task other than another distraction for the brain. So by not having to think on the note, he could concentrate on getting the right buttons...which made his times better. He was basically sight reading on a phone, but could not see it at the time, till we compared the two tasks, now he sight reads on the bass, but still hones his skills on the phone app when bored against the clock.
Could he have got the same result without the phone??? well yes i believe so and know so, but it is for him to believe not me, the app was just a reference for me to help him relate to what he was really doing.