Did you create a relation to show the repeat region index to be 10, 20, 30, etc.? If so, then you will need to create a custom BOM balloon symbol and call out \rpt.rel.<parameter_name>\.
For example, I created a repeat region relation to show my report index as 001, 002, 003, etc. In my relation, I defined parameter test. In my custom symbol, I created a note and called out \rpt.rel.test\. My BOM balloons now show 001, 002, 003, etc.