Don’t quite agree with your ‘standard responses’ there, in terms of the game it may be quite functional but for realism it’s far from it. HEMS wouldn’t really be sent to a head injury unless requested by a ground crew unless the call was like a head injury from a big trauma e.g. fall of a bridge or something but unlikely. And for a cardiac arrest, JRCALC advises 3-4 clinicians, so a DCA + 1 or more resources. It mainly depends on the availability of resources in the area for example if 2 DCAs are the closest they’ll be sent but if 1 DCA and 2 RRVs are closest they’ll be sent. Quite a lot they send more than that basic level often including 1 or more DCAs, 1 or more RRVs, a team leader and HEMS/Advanced Paramedic. The team leader is to coordinate the scene due to a large amount of resources however there would be no need for an officer, officers are tactical command (silver) and would not be needed for this incident as it can be managed by the operational commander (bronze) (team leader).
Read it and understand never said a standard response to a real life ambulance service.
My ambulance service in game standard response. These will provide full cover being sent to a job even if it is not needed. The AO goes so they transport automatically and save me 10 minutes of clearing transports for all my calls.
May not be like real life but to be perfectly honest I'm not going for real life units or responses, the game doesn't follow real life with that side of things so no point in trying to force it to. I'll happilly continue to build my services up.
The closest to real life I use is the locations for stations but even then to cover most things I'm using closed sites and even sites that have no response services at them as to be fair how calls spawn especially HART calls realistic is extremely difficult to replicate. Yes you can do it but calls will sit for hours and build up waiting for resources. So you end up with a ton of calls sitting and your struggling to clear them.
So yes my ambulance service response will be what I say.