I just use a mixed (absolute and relative) range for the series. For example, the first series when you have 3 rows of data could be DynamicChart1!$A$2:$A5 (no dollar sign for the 5). I start out with one more row in the range than I actually have of data. I leave the last row blank or indicate that it is a place holder. To add more data I select the place holder row and insert a new one above it. to eliminate any ill effect from having the last (non-data) row included in the chart you can use zero or functions like MAX($A$2:$A4), MIN($A$2:$A4), or AVERAGE($A$2:$A4), depending on the chart type and how it is used.