Q-drop 88 does not read, '10 days of darkness', it reads '10 days. Darkness.' And drop 97 reads, '10 days. Darnkess.'
Could it be 10 days 'until' darkness? So, yesterday, Good Friday, was 10 days 'until' darkness.
I'm not date-fagging, we will have 'darkness' in nine days, now!
And Easter always seems to fall on different dates, so this could have been calculated as a marker. Who knows?