BT BM 74b(5) :אי פסקת בשער הגבוה שקול כי השתא ואי לא פסקת שקול כדמעיקרא‏ : if you contracted at the lowest price, take according to the present price [lit. that of now]. If you did not contract (so), take according to the original price [lit. that at the beginning]
See the entire entry for psq vb. to come to an end; to cut, to decide