My travel is normally good for QRPC Silver, but with some judicious use of mileage runs and QR's QPoint promos, have got myself to Gold, renewed Gold, and recently got up to Platinum (good for Nov 30 2019 - Nov 29 2020)

It's highly unlikely I'll travel enough this year to retain Platinum, so I'm curious about what will happen when it ends?

1. If there were miles that would've expired during the membership but stayed alive because of the Platinum status, will they disappear on Nov 30th? Or will they stay on to the end of that quarter?

2. Will my new status be calculated only on the last year of travel after status expiry (i.e. 1-year window starting at Dec 1 2019 - Nov 30 2020 and rolling forward)?
what if I had enough points for (say) Gold at an intermediate point - would that be considered? e.g. June 1 2019 - May 31 2020, which would have gotten me a Gold from June 1 2020 to May 31 2021?)

(BTW the reason I'd like to keep at least Gold is for lounge access for me + wife + child, plus priority check in, etc which makes travelling with a child so much easier; and I wouldn't be able to get to Sapphire on other OW carriers flying to CMB)