The manufacturing of engines has changed over the years. New processes using diamond inserts and such mean less break in is needed. But engine rebuilding has not changed much. So break in of overhauled, rebuilt or remanufactured engines need to be broken in the old fashioned way.
I don’t disagree with the way the OP is doing it, but for myself, I’d use conventional multi-vis and change it at 500, 1500, and 3k. If I intended to use synthetic, then I’d start using it at the 3k oil change and then follow my intended interval after that. This has always worked for me.