Thanks!
All of the Firescope docs are listed here: https://firescope.caloes.ca.gov/publications
MACS 441-1 May 11, 2024 is here and will automatically download https://firescope.caloes.ca.gov/ICS Documents/MACS-441 2024.pdf
If you search within the document you'll find that 159.2775 is not exclusively a simplex A/G freq but can be paired for repeater ops
Examples:
151.3325 & 159.2775
155.9025 & 159.2775
For both Cal Fire tacticals and air to grounds there are a few frequencies allocated for initial attack and some are reserved for extended attack, which are only assigned by both North and South Ops. Duplications like the examples you mentioned are coordinated by those GACC's.