The following three verses all discuss the same waiving procedure by the Priest. Note the alternation in the underlined phrases:
• Verse Lv07-30a states His own hands shall bring the offerings of the Lord made by fire, the fat on the breast, he shall bring it, that the breast may be waved for a wave offering before the Lord.
• Verse Lv10-15b states The offered shoulder and the waved breast shall they bring on the offerings made by fire of the fat, to wave it for a wave offering before the Lord; and it shall be yours, and your sons’ with you, by a statute forever; as the Lord has commanded.
• Verse Lv09-20a states And they put the fat on the breasts, and he burned the fat upon the altar;

Rashi comments on the alternation fat on breast vs. breast on fat: As can be clearly seen from the underlined alternations three different people are involved in the offering and each one holds the offering differently
• the owner brings the fat of the animal on the breast (So the fat is above and the breast is below)
• the receiving priest who receives the offered items from the offerer performs the waiving ceremony mentioned in the Bible with the breast on top on the fat on bottom. The waiving priest delivers the offered items to the offering priest - that is, the priest who offers these items on the altar.
• The offering priest has the fat on top on the breast on bottom.

Advanced Rashi: The above Rashi based on a very delicate, but real, alignment introduces many novel ideas about simple vs homiletic meaning. On the one hand the primary intention of the text is not to tell us about 3 players in the offering procedure - rather the primary intention of the text is to tell us about the offering itself. But the aligned language of the text clearly exposes and forces us to infer that there are 3 players - owner, receiving priest who waives, offering priest - who offers the offering.

This distinction between primary intention of the Biblical text and forced inferences, is helpful in understanding the relation between intended meaning, primary meaning and homily. In our article Biblical Formatting we compare the use of alignment by the Biblical Author to the use of footnotes by a modern author. A footnote is intended, is not primary, but is not homily. Similarly the alignment may not be the primary meaning of the text but is an intended meaning and not homily. A student of Rashi who grasps this will find their acceptance of Rashi superior.