Momoshiki aborbed Kinshiki to obtain his chakra and taijutsu skills, so he should be at least 562.7 Exatons by virtue of them both being massively above the like of Toneri whose best feat is 281.35 Exatons for cutting the moon in two. Jigen in his otsutsuki form is much stronger than Momoshiki as he was able to defeat both Naruto and Sasuke with ease. There is an obvious gap in the logic for the verse's AP when Naruto using an immensely stronger form is still only 5-C+.
At least Low 5-B: Otsutsuki Form Jigen, Fused Momoshiki
At least Low 5-C+: Adult Naruto (Sage of Six Paths), Adult Sasuke, Karma Seal Jigen, Momoshiki, Kinshiki, Urashiki, Delta
5-C+: Kaguya, Toneri (Tenseigan Chakra Mode), Teen Naruto (Sage of Six Paths), Teen Sasuke (Rinnegan), Hagoromo, Hamura, The Last Naruto (Kyuubi Chakra Sage Mode)