The most important parameter for account copier is copying speed. What happens when you or your Forex Robot sends order. What happens on slave (sub-account), If you use account copier based on Metatrader 4 scripts (or expert advisors).
Example for order closure request.
16:43:35 ’2345′: close order # 111 buy 1.00 EURCAD
16:43:35 ’2345′: request was accepted by server
16:43:35 ’2345′: request in process
16:43:36 ’2345′: order #111 buy 1.00 EURCAD closed -16:43:36 + 0.51 sec Copier will copy closure request to slave terminal

1 – Master Script on master terminal will orders correspondence between master and slave terminals every T second. T – parameter defines a frequency of main script loop. Usually T = 0.5 – 1 sec.
Master Script will not find order #111 only when it will be closed + T sec.
16:43:36 ’5678′: close order # 111 buy 1.00 EURCAD
16:43:36 ’5678′: request was accepted by server
16:43:36 ’5678′: request in process
16:43:37 ’5678′: order #111 buy 1.00 EURCAD closed

Time difference between time when you or your Forex Robot sends closure request on master terminal and when order will be closed on slave terminal can be up to 3 sec. For this time price can be changed on several pips and this can be very critical for your strategy.
Same situation will be with order opening or order modification.
If you use our PowerTradeCopier , T=0 and order will be opened/modified/closed on 0.5 -1 sec faster. And our company constantly working for speed parameter improvement.
We have developed STP add-on which allows catch modification or closure request on the master terminal and copy it to slave. As soon as you or your Forex robot will send modification request or closure request, copier will copy this command to slave immediately without waiting when the order will be modified or closed on the master terminal. STP add-on has one limitation. PowerTradeCopier and master terminal should be installed on one PC or VPS.
If your strategy has closure condition by Take Profit or Stop Loss only, you can use this add-on for orders opening too.
But if your strategy has other closure conditions, we do not recommend to use STP add-on for orders opening. Because this can lead to abnormal situations when the order was for some reason not accepted by the server on the master account, but has been copied to slave account.
Example for order closure request. (PowerTradeCopier with STP add-on )
16:43:35 ’2345′: close order # 111 buy 1.00 EURCAD closed -> 16:43:35 + 01 sec Copier will copy closure request to slave terminal
16:43:35 ’2345′: request was accepted by server
16:43:35 ’2345′: request in process
16:43:36 ’2345′: order #111 buy 1.00 EURCAD
Feel free to contact us for more information