Trailing stop formula

i've been using trailing stop chosen from analysis "settings" tab. i checked manually to see
if it work OK, and found out it didn't. it seems to get out of trades erraticaly, without any connection to what a trailing stop should do. i looked at this site and saw many very complicated formulas suggested as a trailing stop for users. my question: why does a formula such as:
Sell = Close < HighestSince(Buy, Close) * 0.9; (0.9= if trailing stop is set to 10%, of course)
is not good enough? what am i missing? it seems to me now my stop is working just fine.
Thanks in advance.

@alonhalter, in general, trailing stops use the High to set the current level of stop.

This may explain why the results of the default "stops", using the analysis settings, are not what you expected.

I suggesto to review this KB article that displays 2 different ways to do it (in particular the second one: it uses the High in a condition similar to the one you posted).


Indeed, that seems to be the reason for the difference. Now, that i changed H for C in my formula, it works just like Amibroker trailing stop settings. Thanks, beppe for the prompt reply