Correct. When specifying a support/raft interface material under the Support section in Bambu Studio, you can also set the top z distance to 0 to have the bridge print directly on the support interface instead of leaving an air gap. Bambu’s support for PLA is good, but not perfect - being a PITA to remove in some circumstances (the actual support breaks off easy, but the actual interface layer stays put often on small details requiring some patience to remove. I often use a dental pick set to scrape and get under it.) I find PETG works better and is cheaper. When using any support materials I manually increase the flushing volume when changing from support to main filament to a high value like 800 to avoid weakening the part from mixing materials.
This wiki does a thorough job of explaining support filament:
And this forum post goes over using PETG to support PLA