I was like you, but I had 29 stays last year. I assumed that if they wanted the criteria for Diamond to be 29 stays they would have set it at that level. Likewise, if they wanted Diamond to be 114,000 base points they would have set it there.
Therefore I made an extra stay that I didn't need in order to retain Diamond.
On the positive side, you are Diamond for the next 3 months and will be Gold after that, if you have not re-achieved Diamond by then.
this is very generous and allows those who are late to re-achieve status and brings business to Hilton in the first quarter every year