Copying/Programming EPM7064 and EPM7160

Hope someone can help me here.

I am attempting to copy a set of PLD's ... EPM7064LC44-15, EPM7064LC68-15, EPM7064LC84-15 and EPM7160ELC84-15.

I am using a Dataman 48XP programmer + adaptors to read the contents of the source chips. Although I seem to be able to read the chips ok (and it looks like they are not protected as I can see data), they chips were marked with a checksum, however the checksum marked on them does not match the checksum I get from the Dataman (not even similar in any way). Now I think this may be due to the fact that checksums may be computed differently .... does anyone agree ?.

Also I note that the EEprom range read by the programmer is 000 -- EF2 hex ... can anyone confirm this is the correct range ?

Your help is much appreciated:)