A enchanter can enchant their ring for a total of +38 spell power, which yields +30 enchant pts. However Master's Inscription of the Storm shoulder inscription only yields +15 enchant pts with it being +37 spell power over the next highest enchant.
Ring +19sp 15pts Ring +19sp 15pts Shoulder +24sp 15pts Total 62sp 45pts
Ring 0sp 0pts Ring 0sp opts Shoulder 61sp 15pts Total 61sp 15pts
Looks like Master's Inscription of the Storm should be a 45pt item. Other inscription enchants work out similar.
Enchant scoring system is changed with patch in February : - overall enchant score is re-evaluated and it can now be max 135 for all classes/professions. You can not find any enchanter that can have bigger enchant score then you if you have all best possible enchants.