Yes after your deflection measurements are confirmed, it would warrant a close look.
Drawing 27A, top right corner & cross section G-G, check if F-811D elevator down stop had not been installed, or if was, was over trimmed. Also re-rig elevator linkage and check all geometry is right, when adjusting that linkage remember that auto pilot linkage will also have to be readjusted.
While you are checking this out, check that elevator Up stop is within parameters.
Why worry? In normal flight probably no concern, but stated max deflections probably dictate max permissible deflection loading. I would also be concerned with possible linkage adjustment lengths and thread engagement of the rod end bearings.