Keep in mind platform_rtc_abort_powersave() also expects the spre clock to be ticking each 1.25ms. So above will lead to a lot of RTC inaccuracy. A fix/alternate function would likely just exit powersave without adjusting the rtc.
After looking closer at this issue, I've decided the change is risky and will involve allowing more RTC drift/inaccuracy than I'd like. I will choose instead to limit deep sleep intervals to 30 seconds and revisit later.