If a Bard takes the Sorcerer Dedication and chooses an Occult bloodline...

[Oskar Z.]

... do they use their (higher) Occult proficiency level for their spells chosen from the Sorcerer line? That is, when they hit level 7 and get expert proficiency in Occult spells from their Bard class, so their Sorcerer spells now cast with expert proficiency? Or do they still use Trained proficiency since those spells come from the Sorcerer dedication, which has only Trained at level 7?

[thenobledrake]

the features that give you proficiency in spell attacks and DCs do so by tradition, not by source or by class - so yes, a multi-class character that has the same tradition of spells would use the same proficiency bonus.

[Gisher]

You can only have one proficiency level for each type of proficiency. So a Bard with Expert Occult Spellcasting would still be at Expert level when casting Occult spells from the Sorcerer Multiclass.

It works just like it would with weapons. A 15th level Barbarian doesn't suddenly go back to Trained with daggers because she takes the Fighter Dedication.

[Oskar Z.]

Many thanks for the clarification.

[Captain Zoom]

Small side point:

All of the above is correct, BUT remember that you must use the correct attribute for the check.

In your example, a Bard (CHA Occult) Multiclass Sorceror (CHA Occult) happens to both use CHA, so this wouldn't matter, BUT, for example:

A Cleric (WIS Divine) multiclass Sorceror (CHA Divine) may have slightly different numbers - the character in both cases uses the Cleric's higher Divine spellcasting proficiency, but the character uses WIS when casting cleric spells and CHA when casting Sorceror spells, and the two attributes are probably different.