I to am doing time line video for several constructions sites which now include a well known fast food restaurant. I use POI same height and distance. But only go out as Norm mentioned "noticeable change".
personally I think you and @Norm Kokes
might be leaving some $$ on the table. When we "discuss" with the group hiring us we set up a time frame for taking pictures. We sit down and come up with a set time frame and fly those times regardless of progress. Some projects are weekly, some every other week and some monthly. Regardless of what they've done they need to see that the job site is clean, SAFE, and the project is moving along as anticipated.
We use Litchi and have for a long time now. This way after the first flight they are all identical in terms of height, angle, direction, and position. I spend a LOT of time on-scene the first time with blueprints etc to make sure my flight is safe and efficient and will be able to be done throughout the project. Once in a while I may "tweak" it mid project or have to increase altitude as the construction gets higher but the majority of the flights are identical start to finish.
I just got a contract in the mail yesterday with a national grocery store that is being built about 2 min from my office.