SLA:service profile and response profile

Can anybody explain th use of service profile and response profile?

I mean: when a SLFN transaction is created, with an item category which uses a product with a service profile and response profile, how response times are calculated?

SLFN has its own date profile, and so item category and product too.All these date profiles are different!!

I just want to check SLA times, so need to know which profile is considered and where can i find such kind of information, if there is a report where LSA time are clerly shown and detailed for each message.

I'm using Solman 40, SP 8

Please, help me

Thanks in advance to everybody

Michele