No no no, you stop at lv 4 for the SR. Then just add 7 lv 1 R's. That's 210 points using 1 SR + 13 R's, instead of 1 SR + 15 R's.

And there's no reason to ever level a plain R.

Where are you getting 500 for SSR grail from? I'm looking at Jp wiki right now and it says 400.