You're sitting there assuming that the UNSCEAR report used the total release from Fukushima as part of their analysis... and now they'll be forced to change it in light of the new estimate.
That's simply wrong. I can't think of another, kinder, way to say it to you... you don't know what you're talking about.
Scientists involved in producing the UNSCEAR report hope that their independent summary of the best available data
That's correct. And "the best available data" is not the total release estimate. That isn't data... it's an estimate based on the data.
Lets also consider this idea of a factor of ten. What is that supposed to mean? That is was a tenth, or it was ten times greater?
That's right. You think that it doesn't make sense, but they are saying that they thing the "real" final figure will be somewhere between one tenth and ten times greater. That's because all we have to work with is measurements of activity levels over many months (combined with weather data and the timeline of the accident). UNSCEAR is using those figures to estimate doses (as they should) and Japan is using the same figures to estimate the total release. Both figures are the output of analysis of actual data... they neither rely on one another nor refute one another.
Pay attention now. Imagine that it turns out that Fukushima actually released 100 times as much... but the extra 99% leaked out to an unknown cavern well below the sea floor (so it never impacted any of the radiation readings across the countryside or offshore). The estimate of the total release would have to go up (and the statement that the estimate was thought to be accurate within a factor of ten would need to be corrected), but the dose to the public would not change. So the reports that estimate that dose would not need to change either.
Did the report use the just released data from Tepco that showed much greater >>>100% releases than what UNSCEAR had because Tepco just did release it's numbers.
Nope. What you miss is that they didn't use the new number... or the old number. So the change doesn't imact their analysis at all.
Because even they say they used available data
Indeed they do. But it's you that claims their using something that isn't "data" at all... but an estimate based on an analysis of that data.