Unfortunately, Rien's calculation isn't quite correct:
Price drops to $2,
10.000 (PC) - (1000 shares * $2) = $8,000
$8.000 - 10% safe = Buy order over $7,200 = 3,600 shares
The 10% safe are supposed to be relative to PC, so:
$8.000 - 10% safe (PC 10.000) = Buy order over $7,000 = 3,500 shares
The new PC then becomes 13,500, not a big difference, but a real one. The rest of the calculation:
Share price goes up to $2.20 =>
13.500 - (4500 * 2.2) = $3,600
$3,600 - 10% safe (of 13.500) = Buy order over $2,250.
Now the difference between this $2250 and Rien's $3.000+ is rather great, so take care!
About the flaw: when the share price drops, AIM advises you to buy a certain amount. When the share price remains at that level, AIM might advise another buy, even when the price has risen a bit. It's still good advice: Buy, the price is low enough to justify it. However, you shouldn't go out the next day and buy. Space out your buys, as money is a limited resource in AIM. (Equity never is, so the same doesn't apply equally to sells.)
Regards,
Karel