Why these numbers
Overture PLA starts from Bambu's PLA Basic reference; Overture's published specs are overlaid where available, and everything else stays at Bambu's calibrated default.
TDS V5.1: density 1.21; "patented anti-clog formula"
Treat these as a starting point — run a flow-test cube and Bambu's Flow Dynamics calibration after import for the last few percent.