The map bytes do get written 8x as often as the data set locations, but the bits that are already written do not experience the same stress as bits that are changing from erased to written.
Very interesting, I will ask around about the reduced stress writing what is written.

I notice in your first subroutine FetchEE() that the "offset" variable appears to be uninitialized at the time the code comes to the first while() instruction
I "quick rewrite" from memory, no review done.

Thanx,

Erik