I'm developing a plugin for measuring my water usage. Using a simple reed relay (costs less than 1 euro

I've got it working in the sense that I can detect the pulses and calculate waterflow and usage.
For now, I've been using the Gas and Waterflow device types. As Gas seemed the only one reporting cubic meters, and the flow seems just right.
However, for the usage I only see the value I put in the sValue, if I look at my P1 Electricity meter, next to the current counter value, I also see current usage and usage today.
Now my question is, do I need to put in some fancy sValues to also get these kind of reportings in the Gas device type, or is there some other device type that is better suited for this purpose?
Regards,
Jorg