I have been extracting for several years and I have a simple suggestion that would greatly improve the accuracy of the extraction:
For each record that is extracted, you should be a "COMMENTS" field that is optional in the extraction.
For example, I am extracting Belgium records right now. I just extracted a record where the death month could have been June or July but it was unclear which month it was because of a fold in the page. I had to label the field "Unreadable" because I couldn't fairly differentiate between the two months. Had I been able to put June or July in a "Comments" field, a researcher would then have known more accurately the month of birth.
I could give many other examples but I think the point is made.
Putting in an extra comment field would be simple and relatively inexpensive and would be a valuable tool for researchers.