Hello,
Now I use Intractive Brokers for FX.
However, STOP order consistently slipped from placing price. (generally 3pips ~ 7pips)
A few days before, I had been watching the STP order functioning.
I utilized STOP Sell at the moment, but System doesn't fill the order although Bid price reached to placing price.
It stuffed after price went down to 7pips more.

I ask to IB custom support concerning this behavior.
Their response is:
gt; STOP sell order triggered at Ask price reached to placing price, and stuffed at Market(Bid) price.
Gt; Thus it worked properly.

Then, I've carefully checked the behavior of IB system, it seems to work as under.

STOP sell order
gt;gt;gt;Activate when Ask price reached to placing price, and filled by Bid price.
STOP buy order
gt;gt;gt;Activate when Bid price reached to placing price, and filled by Ask price.

this way, STOP order consistently slip more than (or equal) spread.
It's different behavior from the FX seller I used previously.
Can it be major way in FX seller????
STOP order behavior differs in each FX seller????