The table below presents an aligned extract of verses or verselets in Lv27-31a Both verses/verselets discuss that plant tithe is holy (that is, it can't be eaten like ordinary food but must be eaten in holiness in Jerusalem) The alignment justifies the Rashi assertion that The fifth rule only applies to your tithe that is to tithe of the owner. In other words if the owner redeems his tithe he must pay its value and 25% more while if a non-owner redeems a friends tithe he only pays value without any addition. By contrast the tithe-holiness rule applies to tithe whether of the owner or any other person. In other words tithe is holy (forbidden to be eaten except in a holy state in Jerusalem) whether it is the tithe of the owner or a friend.

Verse	Text of Verse	Rashi comment
Lv27-31a	And if a man will at all redeem any of his tithes, he shall add to it a fifth part.	The fifth rule only applies to your tithe that is to tithe of the owner. In other words if the owner redeems his tithe he must pay its value and 25% more while if a non-owner redeems a friends tithe he only pays value without any addition.
Lv27-30	And all the tithe of the land, whether of the seed of the land, or of the fruit of the tree, is the Lord’s; it is holy to the Lord	By contrast the tithe-holiness rule applies to tithe whether of the owner or any other person. In other words tithe is holy (forbidden to be eaten except in a holy state in Jerusalem) whether it is the tithe of the owner or a friend.