I can't either.
And again, I'm not claiming he didn't rewrite, manuscript evidence clearly shows that he did revise and even recycle poems. Where I think Mr. Martin is stretching things is when he says that there were separate versions sent to, say, Wormwood and Black Sparrow. That would seem to be very unlikely.
One cool thing about having copies of so many manuscripts is in some cases you can see what is essentially same poem, retyped, revised and re-titled, dated many months apart. Since almost all of these manuscripts came from publishers other than Black Sparrow (he did not sign the copies sent to B.S., and these are almost all signed), these are not different versions for books, they are just different versions. Recycled poems.
The mechanics of how Bukowski wrote and submitted are interesting, as are the changes that we know he made himself. But we also know - without question - that changes were made up in Santa Rosa as well. But we will never know the scope of those changes unless Martin one day writes a biography (which he should, if he isn't already) and speaks frankly about the way they worked.
Not to imply that he's dishonest (I really don't want to get into any personality or character assessments of him again), but there are cases where he massages the actual facts. There are also cases where he appears to be confused about certain details (his mistaken recounting in Born Into This of a scene from Crazy Love as being part of Ham On Rye, for instance).
In the end it probably doesn't matter who changed what, and all we can do from where we sit is speculate.