They have been qualified as Roland Garros Champions since RG. That rule applies for every Grand-Slam-winner of a year, no matter if Singles or Doubles, in case they don't qualify anyway by being within the Top 8 of a year.
Yeah, that makes sense, I was just wondering why they would 'announce' they've qualified if everybody already knew they were going to go. The Master Cup website says "two more teams have qualified", but the Cuevas/Horna have not played together in more than a month.
I assume that it's because they are now mathematically out, but it's not as if this was a surprise, and in fact they reached 'qualified' status from the ATP by falling out of contention for the top 8. My problem isn't with the fact that they're in, just that ATP tried to sort of 'hide' the fact they were in hoping they'd get into the top 8, and when it is impossible, they suddenly 'announce' qualification as if it is news. Why not just have them as 'qualified' from June on?