Gantt Chart Question

Hello Again All,

I've taken a crack at the code to amalgamate all 3 tables across 3 sheets into one large one on a new sheet and frustratingly it almost works (Almost being the important word in that sentence.

The Formula I've used (although full disclosure I don't totally understand it myself is

=IF(ROW() < (COUNTA(Sheet1!B:B)+1),INDEX(Sheet1!B:B,ROW()),(IF(ROW() < COUNTA(Sheet1!B:B, Sheet2!B:B),INDEX(Sheet2!B:B,ROW()-COUNTA(Sheet1!B:B)+1),IF(ROW() < COUNTA(Sheet1:Sheet3!B:B),INDEX(Sheet3!B:B,ROW()-COUNTA(Sheet1!B:B)+1)))))

This appears to work to begin with - it populates the Gantt chart alongside the table as per the conditional formatting and it seems tolerant of inserting new rows into the tables in sheets 1 through 3. I only tried it with sheet 1 to be fair but it did automatically incorporates that into the main table on sheet 9 without any issues.

but...

It doesn't show all of the rows in the tables it references. It stops short of showing all of the table in sheet 1 and overlays sheet 3 onto sheet 2 (if that makes sense) This is undoubtedly an issue born from me adapting a formula I found online with little to no knowledge of what it's actually doing, but the bit that has me puzzled is the fact that some of these rows are returning zero - which (unless I understand even less of the formula than I believe I do) shouldn't be an option. I thought the formula should either reference another cell or show "FALSE"