Time measurement can be tricky as they can legitimately be made from different points, though my preferred measurement is time from first hitting the chord (or a switch in some devices) until I can type. But that isn't the only approach.
For example, rough estimate from the time I hit the jump chord to go to my iMac - slight delay till the lights come on, release after lights come on and another delay till they go off. And there can be another slight delay before typing will work. Actually, there are more levels to that last part. Sometimes if I start typing too quick, it will miss the first character or so. If just a slightly longer wait, the first characters may not show up right away, but then they all do (nothing is actually missed - just delayed). Or enough of a delay and everything shows up as soon as I start typing.
Now, before anyone starts panicking about all these delays, normally I can start typing as soon as the lights go out - and the first few letters lag a bit, but they all show up. But the total time from when I hit the chord to when the lights go out is just over two seconds. If I start measuring from when the lights come on, the time is about 1.5 seconds as you report.
However, further complicating the measurement, is that one of the settings for timing is one for the jump chord. I have it set in the middle. If I set it to the faster position, that would reduce the brief wait for the lights to come on.
But hey, the total is just over 2 seconds - it really doesn't matter if I save a half second to me.
My concerns about how long any jump may take (any devices) is when you wait far longer. Oh, instant would be great, though I suspect it wouldn't actually affect what most people do.