I agree, I don't think I was trying to go for that in my comments.  I think it was more me trying to say the read is installed before, union during, and the resulting write after.  It happens to be the write and union are the same during, but the write during is not the same as the write after (which is what I believe I was going for).  TBH this is all a bit hard to word in a way that someone would easily understand if they didn't know the inner workings very well.