I received this email explaining my ‘lost’ income;
Hi Xxxxx,
Thanks for writing back.
The issue has been raised to and checked by out internal team. As far as they analysis goes, the watch time varies your revenue from November and December. In addition to this, we have some other factors to consider when calculating your revenue. These factors include advertiser bidding, advertising availability, and advertiser demand for your videos.
Please let me know if there's anything else.
All the best,
Max
Google YouTube Team
I should add that there was some drop in average View Duration from Nov to Dec to January.
For instance, in November, for the US audience,who contributed close to 80% of Watch time Average View Duration was 16min. In No ember this went down to 14min and in Jan it dropped further to 10min.
So average view duration drops by 12.5% with from Nov Dec but views & Minutes shot by over 300%.
I have concluded that Youtube erred in adjusting my income downwards on Jan 5th without any reason. It is risky admitting and correcting thus.