A cp 12 is in no way a service,if a service is required it should be recorded on the form,if a service is required to keep warrantee up,that should be done if requested separately
After saying above,if customer pleads ignorance when calling many manufacturer's up for a call out and says he thought cp12 covered his requirements to keep up warrantee,they usually say ok but get correct service in future ...(pushing themselves of course)
However as warrantee,s are getting longer and now even the cheaper boilers are being forced to offer them,the manufacturers are starting to apply terms by the letter and refusing call outs or charging if terms not met,do not get involved in the middle of this by making untrue claims about what the cp12 is and what it covers and it does not cover any manufacturer warrantee's and is not designed to do so
imho