Comsec doesn't average, so you will have to work out an average...

Comsec doesn't average, so you will have to work out an average price so that your portfolio will correctly reflect your value.

Say you have bought three parcels of shares of company WES.
X @ A cents, Y @ B cents and Z @ C cents.

The total number of shares is T = X + Y + Z

The total $price paid is P = X xA +Y x B + Z x C

Average price of each share is P/T

I also buy and sell parcels at different prices, but don't bother to update the portfolio until it is only one parcel left.

Comsec doesn't understand or care which parcel you buy or sell. Your accountant does though to work out CGT.