What is the reason for using basket 7 to place arrays of the default value in it?

[vefimov-dev]

GetBucket() returns 7 for default chunk size (128 items), but 7 bucket contains buffers with size for 2048 items.
Should GetBucket() return 3 for default chunk size?

memory-pools/MemoryPools/Memory/Pooling/Utilities.cs

Line 11 in 9d596be

internal static int GetBucket(int size)