I have noticed that the 744 fuel totalizer tends to slightly over-read in descent and under-read in a climb. Next time at TOD take a look at the totalizer, it occasionally creeps up by a couple hundred Kgs as you pitch down. In a go-around, conversely, it begins to under-read.
I once made the mistake of glancing at the totalizer on the lower Eicas during a go-around and was a bit concerned to see almost a ton less than I was expecting... as soon as we levelled off at MAP altitude it started to creep back to where it should have been. I do believe this effect is more pronounced for tank 2 and 3 readings.