Booking.com's review scoring DOES NOT serve its clients (owners) - it is based on mathematical calculations that do nothing to help owners when they are unjustly given a low score by a vindictive or difficult guest. Further, by working in whole units they degrade previous high scores achieved by owners. The way in which Booking.com calculates scores means property owners with high ranking scores will find their overall score will decline, and one uncharacteristic low score can make it impossible for an owner/property to regain its former ranking. Following the awarding of a low score the current system requires the owner/property to receive a significant number of consecutive maximum scores (in double figures) to regain its lost average - a statistically impossible scenario for the owner. This is significantly worse for owners with scores of say 7 to 8 as they have an impossible task of significantly raising their score, no matter how much they put into their property to improve guest experience.
By way of example, a disgruntled guest (angry because he hadn't realised when he booked that the venue was non-smoking, even though it is extensively advertised on Booking.com pages) gave a low score of 4 (the property had been at 9.8 before Booking.com changed the system) - calculations show that 18 consecutive maximum scores of 10 would be needed to regain the previous score! And this would be compounded for owners with lower ranking scores!
In addition to this nightmare scenario for owners is the fact that they have NO protection from vindictive, disgruntled guests who have totally unrealistic or unwarranted expectations and feel they can take out their selfish feelings on by awarding low scores - if Booking.com cared about its owners it would allow them to review the guests or be more supportive in the vetting of guest comments.