Not sure if anyone's noticed but from several months ago Lantis has started submitting transliterated tracklists on iTunes JP (sometimes even in English when they feel like it). The readings appear to match what is submitted to JASRAC.
Example (just add ?l=en to URL):
https://itunes.apple.com/jp/album/id1269995997?l=en
https://itunes.apple.com/jp/album/id1268525435?l=en
Thought someone might find that useful.