We can suggest the following explanation:
In his comments (on the clause, “these are the pekudei”), Rashi seeks to resolve an elementary question: The term “these” references the beginning of a topic. Moreover (as Rashi says at the beginning of parshas Mishpatim) “Wherever the Torah says ‘these,’ it negates what has been stated previously.”
This remark is puzzling: Even if we presume that the phrase, “These are the pekudei of the Mishkan,” refers (not back to the previous parshah, but rather) to the calculation of the donations which appears later in our parshah, in any case, this is still a continuation and conclusion (not a negation) of the previous parshah. That is, after the Torah tells us how the Jewish people donated toward the Mishkan and how their donations served the construction of the Mishkan, Moshe Rabbeinu gave the Jewish people a reckoning of the amounts of the donations and the purposes these donations served.
The question arises: Why does the Torah use the word “these” (meaning, “it negates what has been stated previously”) as opposed to “and these”?
Rashi answers this question by adding that “pekudei of the Mishkan” refers to the calculation of the donations and the accounting of “all of its vessels for all the work in the Mishkan.” In this way, Rashi explains how “in this parshah,” Torah begins a new topic related to the Mishkan, as we will explain.
