honestly couldnt say matey, I just got them to price match. You wont get discounted now for existing labour, see if they can throw in a can or two of oil and just shop around next time... Although going from your Sig, you must be having to spend a small fortune on servicing anyways! Gave up with BMW and my e36 M!
I'll check my receipt after work and let you know if it said service or oil/filter change.