Rashi comments on the word צו at the beginning of our Parsha that it is an expression which implies a necessity for זריזות, alacrity and enthusiasm. He then says that the Torah used the word צו specifically here in order to emphasize that the Korban Olah, which is discussed here, must be done with alacrity despite the fact that the Kohanim will suffer a loss (חסרון כיס) because of it. This is because the Kohanim do not get a portion of this Korban (except the animal's hide) as they do with other Korbanos.
At first glance, this comment of Rashi is a little difficult to understand, since the Kohanim don't actually incur any loss from this Korban. The fact that the Kohanim don't get anything out of it should not be sufficient enough to consider them to be suffering a חסרון כיס, a financial loss. This is especially true since the intention of a Kohein when bringing the Korban Olah should be to serve Hashem, and not to look for any gain from it.
One explanation is that the Torah is trying to teach us a lesson about human nature. Despite a person's aspiration to serve Hashem and do good deeds, a person will nevertheless look for some sort of gain from his actions for himself. The possibility of personal gain will then inspire him to do a much better and more effective job. Perhaps that is the reason why the Kohanim get a portion of all other Korbanos themselves when they do the actual Mitzvah of offering them. If a Kohein is allowed to look for some gain for himself, he'll do a serious job and, in the end, he'll utilize the Mitzvah that he's doing to eventually convert his physical desires into spiritual ones and thereby will elevate himself.
We can therefore say that perhaps Rashi here alludes to this interpretation. The חסרון כיס, the loss, of which he speaks is actually the lack of the opportunity for the Kohein to elevate himself by physically benefitting from the Korban and eventually spiritually elevating himself as well.