just started to use this software. Looks very interesting.

And i got into wandering: what could happened at the point of time between May 11 05:10 and May 11 15:00? Eve-Profit started to show my sells as loss. Selling price didn't change, i checked markets: no changes....

screenshot

Any ideas?
One of possible things i can imagine is got Broker relations to 4 at some point (maybe it was that moment). But i still son't see any reasons why profit became loss?

Note: screenshot shows buy/sell transactions for 1 item. Buy transaction was shown to let you see i (re)bought this item for lower price than i use for sell.

If there is no corresponding Buy order for the item you sold it will show the transaction tax as an amount loss. (1.5% which is your broker fee/sales tax)

Were you selling something you picked up from another character, or made yourself?

Eve profit forks on a fifo basis rather than tagging each item at what the cost was to purchase it as stated above. May have something to do with it.

FIFO is an accounting term meaning first in first out. It is a method of assigning cost to inventory sold and it is the method that eve profit seems to operate under. You can test it yourself. Purchase two of the same items and differing costs, first one cheaper and the other one for more isk. Then sell in reverse order selling the one bought for more isk first. Eve profit is goin to show the profit you made from selling the the first item you bought at the cheaper price since you bought it first.

It doesn't really matter though since they are the sae exact item but I was stating it to build on your post and show how profits on eve profit can be skewed.

well. i checked my accounts transaction history. I dunno how did it happen but i can't find where and when i bought that item. And Eve-Profit shows that i sold more items than bought. My API reader shows the same.

So the idea about "standard tax" looks real.