Mark Date Table after everything

This is an excellent upgrade! I was looking at the dashboards i created a few years ago the other day and i wasn't able to leverage the date table fully back then. 

For your question I would verify if there are continuous date range and make sure there is no gaps in the calendar and it includes all dates needed by fact tables. 

Since you are switching to all Time Intelligence Measures, it's worth testing a few more to compare with manual calculations for critical periods.