tenses - Is choice of verb form or construction determined by context or by a sentence's internal structure?

I'm trying to understand the concept behind the correct usage of tenses. Should I choose the correct tense based on the context or is it strictly constrained to the text within the sentence?

For example I have a phrase like this:

Within a year before the renovation, a total of 10,000 people had
visited the museum, and the majority had voiced dissatisfaction
with their experience.

So basically I'm describing an action 10,000 people had visited the museum which is taking place before the certain event renovation.

Now. I want to add a bit more clarification to this idea and write something like this:

During this time, 40% of the museum guests voiced their dissatisfaction with the
experience.

Now this sentence is in Simple Paste tense, but is it correct? I mean, the overall context is in Past Perfect Simple, as stated by the previous sentence. So should the second be in Past Perfect Simple as well, if it's following the first one as part of the same paragraph?