Meter Readings conversion factor
The conversion factor in the meter settings is used for meters where your measured units are different to your billed units (e.g. m3 vs kWh). As an example my own gas meter measures in cubic feet (ft3), and my most recent bill tells me there are 32.156347 kWh for every cubic foot of gas (just divide the number of kWh you have been billed for by the number of units you have used on your meter).
The true conversion factor changes daily, due to the calorific value of the gas you are supplied with. And this changes based on where you are in the country. Your energy supplier simplifies these complex changes by giving you an average figure per bill.
Back to my app, it would be horribly complicated to track these changes to your conversion factor, so I simply take the single figure you supply and use that for all reading periods. The app is more about making you aware of your usage not the exact amount of each bill.
However if your old gas meter is replaced and you have a completely different conversion factor (e.g. your old ft3 meter is replaced with one that measures in m3), this will change all of your historical costs too. There are two ways around this …
1. Add your new meter as a completely separate meter in the app. You can then set its new conversion factor as before and things will work fine. However you will lose the visual comparison against your older readings.
2. Set your conversion factor to 1 and adjust all your rates (past and present) to be for your metered units. This basically means manually multiplying your kWh rates by your conversion factor to give you your rates per metered unit.
Either way will work, it just depends how much work you want to do.
UPDATE: you can now set the conversion factor as part of a rate change, simply add a rate change and edit the new conversion factor.