请教2条白勇语法题

11．The growth of the railroads led to the abolition of local times, which was determined by when the sun reached the observer's meridian and differing from city to city, and to the establishment of regional times. （E）
（A）which was determined by when the sun reached the observer's meridian and differing
（B）which was determined by when the sun reached the observer's meridian and which differed
（C）which were determined by when the sun reached the observer's meridian and differing
（D）determined by when the sun reached the observer's meridian and differed
（E）determined by when the sun reached the observer's meridian and differing

答案是E, 请问这个differing和and前面的那个部分并列？

6. The guiding principles of the tax plan released by the Treasury Department could have even a greater significance for the economy than the particulars of the plan. （D）
(A) even a greater significance for the economy than
(B) a significance that is even greater for the economy than
(C) even greater significance for the economy than have
(D) even greater significance for the economy than do
(E) a significance even greater for the economy than have

 答案是D，我觉得是E，have不是和even前面那个have对称吗？

谢谢解惑！

6 have在此作为实意动词,不是助动词,因此D选项的do和have并列