No, it’s not true, in fact it’s a gross exaggeration.
What actually happens is that every calender minute you move within is counted as driving time. So, in practice, it records the whole time you were creeping in traffic as driving (which it was, as you were at the wheel and in control of the vehicle) where in the “good old days” on analogue we all used to stop and start our timers only when we actually rolled forward, counting only a couple of seconds at a time. In other words, it counts “drivering” as opposed to “driving”, if you see what I mean.
I was convinced, like many others, that my digitach was robbing me blind…until I had an older analogue motor for a few days whilst mine was in for MOT and actually it only made 10 minutes difference over a day, if that. If anyone tells you they are losing more, they are either lying or need to get their tacho fixed!!!
It’s actually a bit more complicated than this, but it’s late and I’m tired, so that should give you the jist. Basically it records in the spirit of the law where we’d all prefer it to record to the letter.
Hope that makes some kind of sense. If not, I’ll try again when I’ve had a kip!