Rewrite Sheet With Some Saved Values

I previously had a query resolved in this forum when I was trying to write data to multiple sheets but the requirements have now changed and I need to update the script.

I have a multi-sheet workbook that calls a routine to rewrite sheet4 based on values in sheet1 each time sheet4 becomes the active sheet. This script makes single line entries or double line entries in sheet4 depending on whether data appears in one or both of a two specific data cells (col:J,K) in sheet1. However I now need to manually input extra data items into blank cells (col:B,C,J) in sheet4 and retain those data items after input, but each time I make sheet4 the active one it clears the contents of all the cells including the data that I have entered into cols B,C,J. Is there a way of fixing cols B,C,J on sheet4 so that they are not cleared when sheet4 is activated. Or is there a way of writing just the the additional lines added to sheet1 since the sheet4 was previously activated rather than clearing all the data lines written previously into sheet4 and rewriting them all from scratch each time the sheet4 becomes the active one.

I think you will need to see the workbook that I am working on to see how the sheets link and a zipped blank version is attached.