Well, my experience is different. During the interview, officer told me that period before becoming PR is not important in terms of submitting PCC. He said that PCC is not required to be submitted for the period before becoming PR.
This may be different from officer to officee therefore it is better to submit PCC to be on safe side.
It is usually a mistake to answer questions based on how the answer affects the process. The best practice, by far, is to answer questions based on what is a truthful answer to what is asked.
It is remarkable how many forum participants focus on whether they need to provide a police certificate RATHER than simply answering the relevant questions and following the instructions.
Whether an applicant will need to include a police certificate with the application depends on whether the applicant has answered item 10.b "yes." If "yes," the instructions state the applicant needs to EITHER include a police certificate OR explain why not.
Item 10.b DOES NOT ASK if the applicant needs to submit a police certificate. It is NOT appropriate to decide whether a police certificate needs to be included and base the answer to 10.b on that. It goes the other way.
THAT SAID, sure, IRCC is NOT engaged in a GOTCHA game. IRCC does NOT enforce technical requirements (requirements other than those directly affecting qualification) just for the sake of enforcing the requirement. That is, IRCC will not punish or even impose demands on applicants just because they made minor mistakes or did not follow all instructions to the letter.
So sure, many applicants can report they have successfully navigated the process DESPITE not getting every item in the application right, DESPITE a mistake or omission, such as UNTRUTHFULLY answering "no" in response to items like 10.b.
BUT THE IMPORTANCE OF GETTING IT RIGHT SHOULD NOT BE UNDERESTIMATED.
Sure, I too showed up at my interview without a translation of stamps not in one of the official languages. I understood the rules, the requirement, and the risks. Took my chances. No problem. Others, however, encounter a demand for a translation resulting in some or a lot delay. (Factors likely to influence how this goes have been addressed in depth in other topics.)
Sure, more than a few report answering "no" in response to item 10.b (or its corollary in the previous version of the application), despite having been in another country more than 183 days in the preceding four years, and for some this goes OK (one might say they have, in effect, gotten away with it, albeit for some applicants this is OK with IRCC if there is no reason to be concerned the applicant has any foreign criminal charges) BUT many others are advised at the Interview or later they must submit a police certificate, resulting in some or a lot delay. So far I have seen no reports of applicants accused of misrepresentation for this, but it has quite likely damaged some applicant's credibility and contributed to some elevated scrutiny.
BUT AGAIN, THE IMPORTANCE OF GETTING IT RIGHT SHOULD NOT BE UNDERESTIMATED. In particular, even if relatively quite minor, deviating from the instructions or giving an unimportant erroneous response to this or that item CAN BE PROBLEMATIC if there are additional deviations or errors or omissions AND especially so if the combination of deviations or errors or omissions raises suspicions or otherwise weakens the applicant's credibility.
It is best to do it right. It is best to read all questions and respond based on what is asked, truthfully, honestly, accurately and responsively complete, according to the applicant's best understanding. That is what will work the best nearly all the time.
This forum is rife with tales of woe dominated by a failure to follow the instructions or a failure to carefully give accurate and complete responses. For qualified applicants this is avoidable.