Question

Babylonian Talmud, tractate Bava Metzia, chapter 3, 42a:
“Our Rabbis taught: One who goes to measure his threshing floor says, ‘May it be Your will, Lord our God, that You send blessing in the work of our hands.’ Once he begins to measure, he says, ‘Blessed is He who sends blessing upon this heap.’ If he measured and only afterward recited the blessing, this is a vain prayer.”
According to this baraita, is it possible to understand that there are views among the Sages that allow praying for a miracle? (As opposed to the Mishnah in Berakhot that the Rabbi usually cites, which says that after a certain point it is forbidden to pray regarding the sex of the fetus, because that is a prayer for a miracle.) After all, the amount in the threshing floor already exists before the measuring; we simply do not know it, and the prayer is to change that amount.