@Vor The garmin uses Buhlmann ZH-L16c which should be the same as your OSTC (unless thats the *b varient)?

Any reason to think these two would implement the algo differently?

Do you have a preferred algorithm? RGBM seems ok, and pretty close to VPM in terms of the suggested dive plans. So I dont mind diving with it. But I am always a bit untrusting of an algorithm designed for a specific commercial entity and not open to the public for scrutiny.