金剛經纂要刊定記 6.116

6.116

轉轉等者，謂轉捨二障、轉得二果，轉捨轉得故云轉轉。意云：既若轉得菩提，云何不得一法？故成疑也。

Regarding "successively," etc.: it means successively relinquishing the two hindrances and successively obtaining the two fruits; because of successively relinquishing and successively obtaining, it is called "successively." The meaning is: if one successively obtains bodhi, how could one not attain a single dharma? Hence it forms a doubt.