Optionally, rather than having the first date of a project/milestone combination be null, the first date would be the same as the Target Date.
Proj 1 Milestone 1 Date1 Date1
Proj 1 Milestone 1 Date2 Date1
Proj 1 Milestone 1 Date3 Date2
Proj 2 Milestone 1 DateX DateX
Proj 2 Milestone 1 DateY DateX
Proj 2 Milestone 1 DateZ DateY
1 of 1 people found this helpful
Edit your table calculation (by right clicking the Prior Target Date dimension on the rows shelf and selecting Edit Table Calculation), change it from Table (Down) to advanced. Pull Product, Milestone and Target Date (in that order) across into the addressing pane and click OK.
For the 'at the level' option, select Deepest. For restarting every... select 'Milestone'.
Perfect! Thank you for the quick response.