Note down an important thing regarding User interface
Every time a Sales Order is invoiced, by default standard AX report of sales invoice is opened, if print is marked.
So, if you will proceed to create a new report, you will have to make sure your customer accepting it, as sometimes users may say, we don't want to click one more time after generating invoice. Then it may need to code, opening of your report instead of standard AX report, along with generation of invoice