Hopefully making theology simpler to understand! (2 Corinthians 1:12)

And your contribution shall be counted to you as though it were the grain of the threshing floor, and as the fullness of the winepress.
Numbers 18:27, ESV

Ministers receive the tenth from the people and then also tithe, but God sees the minister’s tithe as it’s own separate offering.
This, too, is a shadow of Christ’s substitionary sacrifice, that He offered Himself in our place but it is seen as our own peace offering before God.
His sacrifice, our reward.