The ranking is quite close at the mid-high ranks. There's 4 points of difference between rank 27 and 100 - high fluctuation without manipulation is entirely expected.

Nope, it's manipulated (or broken). Entries gaining hundreds of points, then losing them again in an instant. Just watch for a few minutes, it's a shit show.

Bit unkind mate. It's normal for ELO rankings to update by many points.