[amibroker] Profits calculation in backtester report -- where's the error?

[Flávio Veloso <flavso@xxxxxxxxx>]

Hello all.

I'm trying to design my first system and stumbled upon a discrepancy on 
AB profits calculation on the backtester report that is driving me nuts. 
I searched Google, foruns, AB help files and could find an answer for 
this issue: is AB doing the math right? Is my math wrong? Or maybe 
there's some backtest options that isn't set properly?

This is the result of one trade reported by AB when backtesting my 
system on a stock (only relevant columns included, commissions set to $0 
per trade to make things simpler):

Trade: long
Price: 14.50
Ex. price: 14.75
% chg: 1.72%
Profit: 41.75
Profit %: 1.72%
Shares: 100

However, when doing the math manually I found that the profit is different:

Ex. price - Price = 14.75 - 14.50 = 0.25 (profit per share)

0.25 * 100 = 25.00

So actual profits are $25.00 but AB reports $41.75!

When using actual values for commisions, the AB profit numbers are 
adjusted properly (which indicates that at least commission calculation 
is being done right). However, profits still drift big from my numbers.

ALL trades shows discrepacies in profit calculations. Of course, I'm not 
confident in using the backtester at all.

FYI, I tried using the "Example" system provided with AB (a simple MACD 
crossover) to check if it was my system fault. The results are the same 
-- drifted profit results.

Here's my backtest settings:

Initial Equity: 10000
Periodicity/Positions: Daily/Long
Commissions: 0.00 per trade
Annual interest rate: 0.00%
Range: All quotations
Apply to: Current Symbol
Account margin: 100
Futures mode: No
Def. round lot size: 100
Def. Tick Size 0.01
Drawdowns based on: High/Low prices
Long trades
Buy price: Open
Sell price: Open
Buy delay: 1
Sell delay: 1
Short trades
Short price: Open
Cover price: Open
Short delay: 1
Cover delay: 1
Stops
Maximum loss: disabled
Value: 0.00
Profit target: disabled
Value: 0.00
Exit at stop? no
Trailing stop: disabled
Value: 0.00
Exit at stop? no


Lastly: all securities in my database have the default TickSize=0 and 
PointValue=1 settings

Any help will be GREATLY appreciated!

-- 
Flávio

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