Another question... What is the recommendation of the default gradient factors (GF) settings for recreational diving and doing a dive with no mandatory decompression stops and a maximum of 40 meters deep? The default conservatism of the system is medium (40/85), Is this good for diving with other divers with other computers with different algorithms? Thanks
Everybody want to know this, but it is a wrong question. Decompression algorithms are designed to produce statistically reliable incidence of clinical DCS in their target demographic.
E.g. a Navy is targeting young fit risk-tolerant people so their algorithm may be tuned to greater incidence of DCS than the one targeted at us fat old tourists.
Reliable means there's supposed to be certain number of DCS cases when algorithm is used as designed. If it was not tested for different levels of added conservatism, it is generally not known how that number would change. We know that if you go over the top (100/100) you're running higher risk of DCS and if you go down to ambient pressure (0/0) you won't be able to ever ascend. The in-between part is a bit of an if.
With ZH-L specifically, 100/100 is considered too risky. There is argument against low settings of GF Low in general, and of less than 70-80% of GF High in particular. I.e. 40/85 is a bad setting but it doesn't mater on a no-stop dive -- unless you overstay your NDL.
There is Fraedrich study showing that several algorithms agree in the GF 70-85 range so if you want to keep your chances of DCS to the expected numbers, that's where you'd want to set your GFs. However the process is non-linear so it doesn't follow that setting them lower will reduce your risk, by how much, and up to which point.
There is the probabilistic planner: SAUL that tries to give you estimated risk for a chosen dive but I'm not sure how reliable his numbers are outside of that 70-85 interval.
So nobody in their right mind is going to tell you what numbers to use.