As far as the oneconnect profile goes:
A mask of 0 (default value) causes the system to share reused connections across all source addresses.
A host mask of /32 (that is, all 1 values in binary) causes the system to share only those reused connections originating from the same source address.
You also need to take into account that persistence profiles and SNATs can affect if connections will be reused. When you are using a SNAT or SNAT pool, the server-side source address is translated first and then the OneConnect mask is applied to the translated address.