first of all i want to assure you that no matter how sustained ther trend is , you will find a small retracement enough to give you 20 pips
the system determines this retacement with the help of the parabolic sar and takes advantage of it.

however , if the trend is sustained without a retracement, then the system will not open new trades untill a retracement does occur

and a 30 pip retracement will always occur on the 15 minute chart no matter how strong the trend may be( which means the system can open a new trade and close off all other trades with 20 pip TP (including spread)

some query:
1)how do you decide start the initial trade (BUY or SELL)?
2)when TP hit, does you open new trades? BUY or SELL?

The trade starts with a buy if the first parablic SAR signals a buy trade and vice versa

When the TP is hit the system starts looking for a trade in the opposite direction
I.E it waits for a new signal from Parabolic SAR

NB You must treat BUY and Sell trades completely independent of each other

If an EA is built for this system , then the Ea will be placed on 2 seperate eurchf charts. 1 for buy trades alone and the other for sell trades alone