If you believe your structure has a higher component of acceleration due to being on a tall structure, it makes sense to "elevate" your analysis.

However, it'll be up to the end user if they wish to pay for this analysis and installation. You should run some calculations and issue an opinion for review.

Some additional thoughts:

1) Is a static analysis sufficient at all? My opinion is that if you have 2 separate structures with 2 different natural frequencies, you run the risk of the structures swaying in opposite directions at some point.

2) If buildings can be designed to be "earthquake proof" that it should also be possible for piping structure, too. The question then becomes can we do so cost effectively, and with the structures fulfilling their intended purpose?