I have been using the EST in MS11 for many years but am getting concerned about the validity of some of my results. In all of my testing I always set Margins & Commissions at Zero (preferring to add these on separate Excel studies) and for Default Size I use “Transaction Cost” of $10,000 with an initial equity of $100,000. I expected that this would result in the units purchased for each test being the nearest whole number under ($10,000 divided by purchase price) (Trading Long only with Buy price set at Open with zero slippage and “Realistic Market Prices” left unchecked.)

However when studying the search results in the “Result Details View” under the “Positions Tab” the value of each trade (ie units times purchase price) varies markedly around that $10,000 value, sometimes by up to 15%. And this is what I believe is corrupting my test results.

Can anyone offer a suggestion as to why this is happening or what I should do to avoid it happening? What I am aiming to do is use a fixed value of units purchased, without allowing for any commission or other trading costs, for each system test.