I appreciate you telling us what you need in detail. I wanted to help you achieve your goal, however, the only way to customize the source name is to click the Customize Report tab every time.
Letting us know what works best for you will show our developers what they need to consider in future product updates. I'll be sure to pass this request to them.
In the meantime, you can only save the Item Actual Cost Detail report by using the Memorize option.
As always, you can visit our Firm of the Future site to get the latest news and updates about QuickBooks and what our Product Team is working on.
Please post again if you have other questions. I'm always here and ready to help. Take care and have a great weekend.