This would be the best option to implement and it will not bring repetitive complaint/question every single month.
They can do it for the weekly bonus so it should not be a big problem for them to implement it for the monthly bonus.
IMO, they want engagement with the user.
I know it's still about complaining, but every people who are commended (went monthly) is gonna give them engagement on twitter. Make their twitter live & have many comment interaction.
It's good for statistic and impression, so they're gonna to stay like that.