Milestone reporting

Hello all,
The organization I work for is piloting Wrike for managing 20-30 projects at a time in the construction industry. 
We probably do about 300 projects a year so it's a reasonable volume of work.
I have set up 10 blueprints to reflect the types of projects. Each project has around 3-6 milestones that are the same for each blueprint. 
I create the projects using the blueprints, quote scope details and intended start dates. The problem we are facing is we are constantly shifting tasks and milestones.
Basically I want to reduce the administration work (as I will get more involvement with colleagues) by producing a report every day that indicates how much time we went over the different milestones so I can then adjust the new projects to reflect this. I am guessing over time we will start to see some trends.
OR am i doing it wrong and I shouldn't be shifting the milestones?
Any feedback on best practices for this kind of scenario would be really helpful.

Thank you