jj,
I've managed, I think, to reproduce your chart from permalink #973. It's a five minute chart, right?
Many pages ago on this thread, I recommended an enhancement to
VSA in which volume would be broken down into volume up vs volume down. The "experts" on the thread didn't like my idea, but here's an example where it is valuable (in fact, invaluable). See attached chart. On your putative upthrust, the total volume is too high, but just as importantly, the upvolume nearly matches the downvolume (upvolume is seen as a green line inside the wider red line which is downvolume). This clearly shows that there was significant buying on this bar, hence it was not an upthrust. The total volume itself would have been a clue, but the picture is clearer if you separate the up from the down.