The problem with answering questions like this is that we have no idea what they were talking about. What seems more important is your current needs and any consequential work that would be considered proper to do at the same time.
As I pointed out, the cell replacement is easy and requires no other equipment removal. it will not be any benefit to do any other work at the same time.
IF, you have an issue left to deal with, there is no advantage to trying to find it at this moment. Fix the system so that it functions properly, which the cells likely will accomplish.
It's possible that you are talking about considerations of original spring height. The hydraulic support is only supposed to lift so much. The steel springs should maintain a certain height. This used to be a problem with the hydropneumatic compensator struts. I don't think its much of a concern in an SEL; unless you expect to carry heavy loads.
Bosch Master, ASE Master, L1
33 years MB technician