Mark – I have written a blog on this topic. https://bsaiprasad.wordpress.com/2014/09/30/how-to-calculate-planned-complete/. This blog is written with the requirement to calculate only planned % complete as on status date field (which is sent in Project tab). Your requirement is to besides (actual) % complete on the current date, you also want to know the planned % complete on the current date and planned % complete on a different date.
So, follow the same instructions in that blog post. After pasting these formula in Number1 and Text1, replace [Status Date] with [Current Date]. Next set the Status Date in Project tab to next week Thursday. Now, insert a Number2 and Text2 field with the same formula in the blog that reads [Status Date].
With these changes [Text1] will display the planned % complete on current date and [Text2] will display the planned % complete on status date.