Glowmarkt API documentation

Version 1.7 of this document gives a good starter for 10 to access DCC data via the Glowmarkt API. On page 7 it states that "Electricity only customers will have two resources (electricity energy, electricity cost)." I am in this situation but the virtual entity with the full definition of resources response provides me with an object containing an array of four resources:

0 - “description":"electicity cost DCC SM profile reads”,

1 - “description":"electicity consumption DCC SM profile reads”,

2 - “description":"adhoc electricity consumption”,

3 - “description":"adhoc electricity cost”,

Can anyone explain what the difference is between these resources? I'm assuming that I should be making use of the first and second resources rather than the other two for completeness of data. Does anybody know why the later two are there at all?