Performance affected by Deep Linking

We had a Crystal Report that on average took 10 minutes to run. A job was logged that the report was taking a very long time to run when a certain set of criteria was specified. On running this report with this criteria, the report had not completed generating after 2 hours. So on analysing the report I discoved it had 'deep links'.

What I mean by deep links is that table A links to table B which then links to table C which then links to table D and so on. What I did was change the linking structure so that table A links to table C and table A also links to Table D, thus going from 4 levels of linking to 2 levels. By removing this 'deep linking' the time taken to generate the reports was now 5 minutes irrespective of the criteria specified.