Ths question follows on that of F.Bachofner in December 2018 - see link text - and I have exactly the same issue.
I have a spreadsheet containing a graph with five data-series and a variable number of blanks at the end of each column of data. Some formulae create blank cells using formulae like IF(–,"",–) which I think creates zero-length strings. This spreadsheet is updated almost every day, however updating each data-series with the last non-blank cell in a column is tedious and error prone.
Configuring each data-series to the last cell in a column ( e.g. Sheet1.$A$2:$A$123) means the series are automatically updated as rows are added, but will the graphing software treat the blanks as not-data? This does seem to work, but I’d be grateful for clarification.
David L.