We've picked up an error with the weight summaries on ASD 2013.

Our tables are printed on A4 sheets in booklet form. This means that the tables are split. Especially when we do slab rebar.
The setup was as follows when we picked up the error.
Table 1 - Bars 1-20
Table 2 - Bars 21-40

If you create a summary table by picking each table you do not get the same values as when choosing the bar positions.

Has anyone else experienced this...?
How do we fix / prevent it