// also added OS/OB lines based on stddev, though commented out at the moment so to not overload the graph.
The TVB is meant to deliver zero whenever close=open=high=low and this is the reason for the 3 multiplying the closing price and the sign of all coefficients.
The formula you suggested, i.e., 3*close-(open-high-close) does something completely different, not even slightly different :)
You might play with the coefficients a bit, e.g. by giving more importance to the opening price by using 4*close-2*open-high-low (try it), but the coefficients have to sum up to zero.
Another pretty modification would be dividing TVB by the ATR and multiply by 100 to have an OS/OB oscillator.
Dividing by the point value is pointless (sorry for the play on words...) unless you hate long decimals.