Is there a way to "rebuild" an accumulator feed?

Hi there,
I’ve managed to connect my gas meter (Schlumberger R5) to my emonPi, using the pulse counter in the meter (and its RJ11 connector).
I’m logging this to a feed. I have been doing this for a few days.

I now want to create a feed that accumulates the pulse counter (making sure it keeps increasing even after a reset which would bring the counter back to 0). After that, I want to create a second feed that will convert the accumulated value into a kwh (using the feet/m3 to kwh calculation indicated on my gas bill).

The question is: I think I see how to go about doing all this - but is there a way of populating the new feeds with the back data since the pulse input started registering data?
I was hoping that there would be a post-process mechanism to do so, but (unless I’m mistaken), I don’t see any simple accumulator (the “power to kwh” obviously wouldn’t work here…)


the Post Processor accumulator did not work?