Issues with not being able to scroll through time periods is resolved as of 15.4.1. Additionally, in Step 7 of the portlet creation, ensure that in the Column Sorting section set the first field to either Investment Name or Investment Code and then click 'Save', otherwise you can still see issues.
Note: You can only scroll through through the cost plan periods available for the investments on the current page of the portlet. Example: If the earliest cost plan date date starts in May 2018 for the current page of the portlet, you won't be able to scroll to any period prior to 5/1/18, since there is no data available for those periods.
Workaround: Change the settings manually in the 'Time-Scaled Value' section to see the periods:
1. Click the 'Options' icon then 'Time-scaled Value'
2. Adjust the Start Date / Number of Time Periods to temporarily see future time periods
3. If you then click the left (Previous Periods) arrow to see future time periods again, go back into Options->Time-scaled Value and click 'Save and Return' to have the TSV reset