After I first landed as an immigrant, I maintained my residence in the USA for a few months and made many (at least 20) short trips to Canada (with PRTD & PR card) before settling permanently in Canada, which was around 40 days in total. I stayed at hotels and did not have a permanent address. I used a UPS mailbox for all my Canadian banking and PR card.
When submitting my citizenship application, is it okay to claim that my residential address was in the US during those months? Those trips (or "reverse absence" from Canada) will of course be listed in physical absence calculator.
As noted above, you do need to list addresses. I would also suggest you have a decent buffer in your presence count just in case IRCC counts those days differently than you do.