Actually, the code I wrote above won't do at all. It won't calculate any indicator values for startup.

Its no good just wrapping the 'plot' calls in an if(!is(LOOKBACK)) statement either since the problem is not a charting issue - the issue is that the incorrect indicator values are being used to trigger trades incorrectly.

What about this for a simple workaround:
Code:
if (priceLow[0] < 0.5 * priceLow[1]) 
  priceLow[0] = priceLow[1];



Not an ideal solution since some information is lost (the actual lowest price of the previous bar), but at least it would prevent drastic changes to the way the script trades.

Any other ideas?